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*/
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * The Internet Protocol (IP) module.
7 *
8 * Version: @(#)ip.c 1.0.16b 9/1/93
9 *
10 * Authors: Ross Biro, <bir7@leland.Stanford.Edu>
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Donald Becker, <becker@super.org>
13 * Alan Cox, <gw4pts@gw4pts.ampr.org>
14 * Richard Underwood
15 *
16 * Fixes:
17 * Alan Cox : Commented a couple of minor bits of surplus code
18 * Alan Cox : Undefining IP_FORWARD doesn't include the code
19 * (just stops a compiler warning).
20 * Alan Cox : Frames with >=MAX_ROUTE record routes, strict routes or loose routes
21 * are junked rather than corrupting things.
22 * Alan Cox : Frames to bad broadcast subnets are dumped
23 * We used to process them non broadcast and
24 * boy could that cause havoc.
25 * Alan Cox : ip_forward sets the free flag on the
26 * new frame it queues. Still crap because
27 * it copies the frame but at least it
28 * doesn't eat memory too.
29 * Alan Cox : Generic queue code and memory fixes.
30 * Fred Van Kempen : IP fragment support (borrowed from NET2E)
31 * Gerhard Koerting: Forward fragmented frames correctly.
32 * Gerhard Koerting: Fixes to my fix of the above 8-).
33 * Gerhard Koerting: IP interface addressing fix.
34 * Linus Torvalds : More robustness checks
35 * Alan Cox : Even more checks: Still not as robust as it ought to be
36 * Alan Cox : Save IP header pointer for later
37 * Alan Cox : ip option setting
38 * Alan Cox : Use ip_tos/ip_ttl settings
39 * Alan Cox : Fragmentation bogosity removed
40 * (Thanks to Mark.Bush@prg.ox.ac.uk)
41 * Dmitry Gorodchanin : Send of a raw packet crash fix.
42 * Alan Cox : Silly ip bug when an overlength
43 * fragment turns up. Now frees the
44 * queue.
45 * Linus Torvalds/ : Memory leakage on fragmentation
46 * Alan Cox : handling.
47 * Gerhard Koerting: Forwarding uses IP priority hints
48 * Teemu Rantanen : Fragment problems.
49 * Alan Cox : General cleanup, comments and reformat
50 * Alan Cox : SNMP statistics
51 * Alan Cox : BSD address rule semantics. Also see
52 * UDP as there is a nasty checksum issue
53 * if you do things the wrong way.
54 * Alan Cox : Always defrag, moved IP_FORWARD to the config.in file
55 * Alan Cox : IP options adjust sk->priority.
56 * Pedro Roque : Fix mtu/length error in ip_forward.
57 * Alan Cox : Avoid ip_chk_addr when possible.
58 * Richard Underwood : IP multicasting.
59 * Alan Cox : Cleaned up multicast handlers.
60 * Alan Cox : RAW sockets demultiplex in the BSD style.
61 * Gunther Mayer : Fix the SNMP reporting typo
62 * Alan Cox : Always in group 224.0.0.1
63 *
64 * To Fix:
65 * IP option processing is mostly not needed. ip_forward needs to know about routing rules
66 * and time stamp but that's about all. Use the route mtu field here too
67 * IP fragmentation wants rewriting cleanly. The RFC815 algorithm is much more efficient
68 * and could be made very efficient with the addition of some virtual memory hacks to permit
69 * the allocation of a buffer that can then be 'grown' by twiddling page tables.
70 * Output fragmentation wants updating along with the buffer management to use a single
71 * interleaved copy algorithm so that fragmenting has a one copy overhead. Actual packet
72 * output should probably do its own fragmentation at the UDP/RAW layer. TCP shouldn't cause
73 * fragmentation anyway.
74 *
75 * This program is free software; you can redistribute it and/or
76 * modify it under the terms of the GNU General Public License
77 * as published by the Free Software Foundation; either version
78 * 2 of the License, or (at your option) any later version.
79 */
80
81 #include <asm/segment.h>
82 #include <asm/system.h>
83 #include <linux/types.h>
84 #include <linux/kernel.h>
85 #include <linux/sched.h>
86 #include <linux/string.h>
87 #include <linux/errno.h>
88 #include <linux/socket.h>
89 #include <linux/sockios.h>
90 #include <linux/in.h>
91 #include <linux/inet.h>
92 #include <linux/netdevice.h>
93 #include <linux/etherdevice.h>
94 #include "snmp.h"
95 #include "ip.h"
96 #include "protocol.h"
97 #include "route.h"
98 #include "tcp.h"
99 #include <linux/skbuff.h>
100 #include "sock.h"
101 #include "arp.h"
102 #include "icmp.h"
103 #include "raw.h"
104 #include "igmp.h"
105 #include <linux/ip_fw.h>
106
107 #define CONFIG_IP_DEFRAG
108
109 extern int last_retran;
110 extern void sort_send(struct sock *sk);
111
112 #define min(a,b) ((a)<(b)?(a):(b))
113 #define LOOPBACK(x) (((x) & htonl(0xff000000)) == htonl(0x7f000000))
114
115 /*
116 * SNMP management statistics
117 */
118
119 #ifdef CONFIG_IP_FORWARD
120 struct ip_mib ip_statistics={1,64,}; /* Forwarding=Yes, Default TTL=64 */
121 #else
122 struct ip_mib ip_statistics={0,64,}; /* Forwarding=No, Default TTL=64 */
123 #endif
124
125 #ifdef CONFIG_IP_MULTICAST
126
127 struct ip_mc_list *ip_mc_head=NULL;
128
129 #endif
130
131 /*
132 * Handle the issuing of an ioctl() request
133 * for the ip device. This is scheduled to
134 * disappear
135 */
136
137 int ip_ioctl(struct sock *sk, int cmd, unsigned long arg)
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*/
138 {
139 switch(cmd)
140 {
141 default:
142 return(-EINVAL);
143 }
144 }
145
146
147 /* these two routines will do routing. */
148
149 static void
150 strict_route(struct iphdr *iph, struct options *opt)
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*/
151 {
152 }
153
154
155 static void
156 loose_route(struct iphdr *iph, struct options *opt)
/* */
157 {
158 }
159
160
161
162
163 /* This routine will check to see if we have lost a gateway. */
164 void
165 ip_route_check(unsigned long daddr)
/* */
166 {
167 }
168
169
170 #if 0
171 /* this routine puts the options at the end of an ip header. */
172 static int
173 build_options(struct iphdr *iph, struct options *opt)
/* */
174 {
175 unsigned char *ptr;
176 /* currently we don't support any options. */
177 ptr = (unsigned char *)(iph+1);
178 *ptr = 0;
179 return (4);
180 }
181 #endif
182
183
184 /*
185 * Take an skb, and fill in the MAC header.
186 */
187
188 static int ip_send(struct sk_buff *skb, unsigned long daddr, int len, struct device *dev, unsigned long saddr)
/* */
189 {
190 int mac = 0;
191
192 skb->dev = dev;
193 skb->arp = 1;
194 if (dev->hard_header)
195 {
196 /*
197 * Build a hardware header. Source address is our mac, destination unknown
198 * (rebuild header will sort this out)
199 */
200 mac = dev->hard_header(skb->data, dev, ETH_P_IP, NULL, NULL, len, skb);
201 if (mac < 0)
202 {
203 mac = -mac;
204 skb->arp = 0;
205 skb->raddr = daddr; /* next routing address */
206 }
207 }
208 return mac;
209 }
210
211 int ip_id_count = 0;
212
213 /*
214 * This routine builds the appropriate hardware/IP headers for
215 * the routine. It assumes that if *dev != NULL then the
216 * protocol knows what it's doing, otherwise it uses the
217 * routing/ARP tables to select a device struct.
218 */
219 int ip_build_header(struct sk_buff *skb, unsigned long saddr, unsigned long daddr,
/* */
220 struct device **dev, int type, struct options *opt, int len, int tos, int ttl)
221 {
222 static struct options optmem;
223 struct iphdr *iph;
224 struct rtable *rt;
225 unsigned char *buff;
226 unsigned long raddr;
227 int tmp;
228 unsigned long src;
229
230 buff = skb->data;
231
232 /*
233 * See if we need to look up the device.
234 */
235
236 #ifdef CONFIG_INET_MULTICAST
237 if(MULTICAST(daddr) && *dev==NULL && skb->sk && *skb->sk->ip_mc_name)
238 *dev=dev_get(skb->sk->ip_mc_name);
239 #endif
240 if (*dev == NULL)
241 {
242 if(skb->localroute)
243 rt = ip_rt_local(daddr, &optmem, &src);
244 else
245 rt = ip_rt_route(daddr, &optmem, &src);
246 if (rt == NULL)
247 {
248 ip_statistics.IpOutNoRoutes++;
249 return(-ENETUNREACH);
250 }
251
252 *dev = rt->rt_dev;
253 /*
254 * If the frame is from us and going off machine it MUST MUST MUST
255 * have the output device ip address and never the loopback
256 */
257 if (LOOPBACK(saddr) && !LOOPBACK(daddr))
258 saddr = src;/*rt->rt_dev->pa_addr;*/
259 raddr = rt->rt_gateway;
260
261 opt = &optmem;
262 }
263 else
264 {
265 /*
266 * We still need the address of the first hop.
267 */
268 if(skb->localroute)
269 rt = ip_rt_local(daddr, &optmem, &src);
270 else
271 rt = ip_rt_route(daddr, &optmem, &src);
272 /*
273 * If the frame is from us and going off machine it MUST MUST MUST
274 * have the output device ip address and never the loopback
275 */
276 if (LOOPBACK(saddr) && !LOOPBACK(daddr))
277 saddr = src;/*rt->rt_dev->pa_addr;*/
278
279 raddr = (rt == NULL) ? 0 : rt->rt_gateway;
280 }
281
282 /*
283 * No source addr so make it our addr
284 */
285 if (saddr == 0)
286 saddr = src;
287
288 /*
289 * No gateway so aim at the real destination
290 */
291 if (raddr == 0)
292 raddr = daddr;
293
294 /*
295 * Now build the MAC header.
296 */
297
298 tmp = ip_send(skb, raddr, len, *dev, saddr);
299 buff += tmp;
300 len -= tmp;
301
302 /*
303 * Book keeping
304 */
305
306 skb->dev = *dev;
307 skb->saddr = saddr;
308 if (skb->sk)
309 skb->sk->saddr = saddr;
310
311 /*
312 * Now build the IP header.
313 */
314
315 /*
316 * If we are using IPPROTO_RAW, then we don't need an IP header, since
317 * one is being supplied to us by the user
318 */
319
320 if(type == IPPROTO_RAW)
321 return (tmp);
322
323 iph = (struct iphdr *)buff;
324 iph->version = 4;
325 iph->tos = tos;
326 iph->frag_off = 0;
327 iph->ttl = ttl;
328 iph->daddr = daddr;
329 iph->saddr = saddr;
330 iph->protocol = type;
331 iph->ihl = 5;
332 skb->ip_hdr = iph;
333
334 /* Setup the IP options. */
335 #ifdef Not_Yet_Avail
336 build_options(iph, opt);
337 #endif
338 #ifdef CONFIG_IP_FIREWALL
339 if(!ip_fw_chk(iph,ip_fw_blk_chain))
340 return -EPERM;
341 #endif
342
343 return(20 + tmp); /* IP header plus MAC header size */
344 }
345
346
347 static int
348 do_options(struct iphdr *iph, struct options *opt)
/* */
349 {
350 unsigned char *buff;
351 int done = 0;
352 int i, len = sizeof(struct iphdr);
353
354 /* Zero out the options. */
355 opt->record_route.route_size = 0;
356 opt->loose_route.route_size = 0;
357 opt->strict_route.route_size = 0;
358 opt->tstamp.ptr = 0;
359 opt->security = 0;
360 opt->compartment = 0;
361 opt->handling = 0;
362 opt->stream = 0;
363 opt->tcc = 0;
364 return(0);
365
366 /* Advance the pointer to start at the options. */
367 buff = (unsigned char *)(iph + 1);
368
369 /* Now start the processing. */
370 while (!done && len < iph->ihl*4) switch(*buff) {
371 case IPOPT_END:
372 done = 1;
373 break;
374 case IPOPT_NOOP:
375 buff++;
376 len++;
377 break;
378 case IPOPT_SEC:
379 buff++;
380 if (*buff != 11) return(1);
381 buff++;
382 opt->security = ntohs(*(unsigned short *)buff);
383 buff += 2;
384 opt->compartment = ntohs(*(unsigned short *)buff);
385 buff += 2;
386 opt->handling = ntohs(*(unsigned short *)buff);
387 buff += 2;
388 opt->tcc = ((*buff) << 16) + ntohs(*(unsigned short *)(buff+1));
389 buff += 3;
390 len += 11;
391 break;
392 case IPOPT_LSRR:
393 buff++;
394 if ((*buff - 3)% 4 != 0) return(1);
395 len += *buff;
396 opt->loose_route.route_size = (*buff -3)/4;
397 buff++;
398 if (*buff % 4 != 0) return(1);
399 opt->loose_route.pointer = *buff/4 - 1;
400 buff++;
401 buff++;
402 for (i = 0; i < opt->loose_route.route_size; i++) {
403 if(i>=MAX_ROUTE)
404 return(1);
405 opt->loose_route.route[i] = *(unsigned long *)buff;
406 buff += 4;
407 }
408 break;
409 case IPOPT_SSRR:
410 buff++;
411 if ((*buff - 3)% 4 != 0) return(1);
412 len += *buff;
413 opt->strict_route.route_size = (*buff -3)/4;
414 buff++;
415 if (*buff % 4 != 0) return(1);
416 opt->strict_route.pointer = *buff/4 - 1;
417 buff++;
418 buff++;
419 for (i = 0; i < opt->strict_route.route_size; i++) {
420 if(i>=MAX_ROUTE)
421 return(1);
422 opt->strict_route.route[i] = *(unsigned long *)buff;
423 buff += 4;
424 }
425 break;
426 case IPOPT_RR:
427 buff++;
428 if ((*buff - 3)% 4 != 0) return(1);
429 len += *buff;
430 opt->record_route.route_size = (*buff -3)/4;
431 buff++;
432 if (*buff % 4 != 0) return(1);
433 opt->record_route.pointer = *buff/4 - 1;
434 buff++;
435 buff++;
436 for (i = 0; i < opt->record_route.route_size; i++) {
437 if(i>=MAX_ROUTE)
438 return 1;
439 opt->record_route.route[i] = *(unsigned long *)buff;
440 buff += 4;
441 }
442 break;
443 case IPOPT_SID:
444 len += 4;
445 buff +=2;
446 opt->stream = *(unsigned short *)buff;
447 buff += 2;
448 break;
449 case IPOPT_TIMESTAMP:
450 buff++;
451 len += *buff;
452 if (*buff % 4 != 0) return(1);
453 opt->tstamp.len = *buff / 4 - 1;
454 buff++;
455 if ((*buff - 1) % 4 != 0) return(1);
456 opt->tstamp.ptr = (*buff-1)/4;
457 buff++;
458 opt->tstamp.x.full_char = *buff;
459 buff++;
460 for (i = 0; i < opt->tstamp.len; i++) {
461 opt->tstamp.data[i] = *(unsigned long *)buff;
462 buff += 4;
463 }
464 break;
465 default:
466 return(1);
467 }
468
469 if (opt->record_route.route_size == 0) {
470 if (opt->strict_route.route_size != 0) {
471 memcpy(&(opt->record_route), &(opt->strict_route),
472 sizeof(opt->record_route));
473 } else if (opt->loose_route.route_size != 0) {
474 memcpy(&(opt->record_route), &(opt->loose_route),
475 sizeof(opt->record_route));
476 }
477 }
478
479 if (opt->strict_route.route_size != 0 &&
480 opt->strict_route.route_size != opt->strict_route.pointer) {
481 strict_route(iph, opt);
482 return(0);
483 }
484
485 if (opt->loose_route.route_size != 0 &&
486 opt->loose_route.route_size != opt->loose_route.pointer) {
487 loose_route(iph, opt);
488 return(0);
489 }
490
491 return(0);
492 }
493
494 /*
495 * This is a version of ip_compute_csum() optimized for IP headers, which
496 * always checksum on 4 octet boundaries.
497 */
498
499 static inline unsigned short ip_fast_csum(unsigned char * buff, int wlen)
/* */
500 {
501 unsigned long sum = 0;
502
503 if (wlen)
504 {
505 unsigned long bogus;
506 __asm__("clc\n"
507 "1:\t"
508 "lodsl\n\t"
509 "adcl %3, %0\n\t"
510 "decl %2\n\t"
511 "jne 1b\n\t"
512 "adcl $0, %0\n\t"
513 "movl %0, %3\n\t"
514 "shrl $16, %3\n\t"
515 "addw %w3, %w0\n\t"
516 "adcw $0, %w0"
517 : "=r" (sum), "=S" (buff), "=r" (wlen), "=a" (bogus)
518 : "0" (sum), "1" (buff), "2" (wlen));
519 }
520 return (~sum) & 0xffff;
521 }
522
523 /*
524 * This routine does all the checksum computations that don't
525 * require anything special (like copying or special headers).
526 */
527
528 unsigned short ip_compute_csum(unsigned char * buff, int len)
/* */
529 {
530 unsigned long sum = 0;
531
532 /* Do the first multiple of 4 bytes and convert to 16 bits. */
533 if (len > 3)
534 {
535 __asm__("clc\n"
536 "1:\t"
537 "lodsl\n\t"
538 "adcl %%eax, %%ebx\n\t"
539 "loop 1b\n\t"
540 "adcl $0, %%ebx\n\t"
541 "movl %%ebx, %%eax\n\t"
542 "shrl $16, %%eax\n\t"
543 "addw %%ax, %%bx\n\t"
544 "adcw $0, %%bx"
545 : "=b" (sum) , "=S" (buff)
546 : "0" (sum), "c" (len >> 2) ,"1" (buff)
547 : "ax", "cx", "si", "bx" );
548 }
549 if (len & 2)
550 {
551 __asm__("lodsw\n\t"
552 "addw %%ax, %%bx\n\t"
553 "adcw $0, %%bx"
554 : "=b" (sum), "=S" (buff)
555 : "0" (sum), "1" (buff)
556 : "bx", "ax", "si");
557 }
558 if (len & 1)
559 {
560 __asm__("lodsb\n\t"
561 "movb $0, %%ah\n\t"
562 "addw %%ax, %%bx\n\t"
563 "adcw $0, %%bx"
564 : "=b" (sum), "=S" (buff)
565 : "0" (sum), "1" (buff)
566 : "bx", "ax", "si");
567 }
568 sum =~sum;
569 return(sum & 0xffff);
570 }
571
572 /*
573 * Check the header of an incoming IP datagram. This version is still used in slhc.c.
574 */
575
576 int ip_csum(struct iphdr *iph)
/* */
577 {
578 return ip_fast_csum((unsigned char *)iph, iph->ihl);
579 }
580
581 /*
582 * Generate a checksum for an outgoing IP datagram.
583 */
584
585 void ip_send_check(struct iphdr *iph)
/* */
586 {
587 iph->check = 0;
588 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
589 }
590
591 /************************ Fragment Handlers From NET2E **********************************/
592
593
594 /*
595 * This fragment handler is a bit of a heap. On the other hand it works quite
596 * happily and handles things quite well.
597 */
598
599 static struct ipq *ipqueue = NULL; /* IP fragment queue */
600
601 /*
602 * Create a new fragment entry.
603 */
604
605 static struct ipfrag *ip_frag_create(int offset, int end, struct sk_buff *skb, unsigned char *ptr)
/* */
606 {
607 struct ipfrag *fp;
608
609 fp = (struct ipfrag *) kmalloc(sizeof(struct ipfrag), GFP_ATOMIC);
610 if (fp == NULL)
611 {
612 printk("IP: frag_create: no memory left !\n");
613 return(NULL);
614 }
615 memset(fp, 0, sizeof(struct ipfrag));
616
617 /* Fill in the structure. */
618 fp->offset = offset;
619 fp->end = end;
620 fp->len = end - offset;
621 fp->skb = skb;
622 fp->ptr = ptr;
623
624 return(fp);
625 }
626
627
628 /*
629 * Find the correct entry in the "incomplete datagrams" queue for
630 * this IP datagram, and return the queue entry address if found.
631 */
632
633 static struct ipq *ip_find(struct iphdr *iph)
/* */
634 {
635 struct ipq *qp;
636 struct ipq *qplast;
637
638 cli();
639 qplast = NULL;
640 for(qp = ipqueue; qp != NULL; qplast = qp, qp = qp->next)
641 {
642 if (iph->id== qp->iph->id && iph->saddr == qp->iph->saddr &&
643 iph->daddr == qp->iph->daddr && iph->protocol == qp->iph->protocol)
644 {
645 del_timer(&qp->timer); /* So it doesn't vanish on us. The timer will be reset anyway */
646 sti();
647 return(qp);
648 }
649 }
650 sti();
651 return(NULL);
652 }
653
654
655 /*
656 * Remove an entry from the "incomplete datagrams" queue, either
657 * because we completed, reassembled and processed it, or because
658 * it timed out.
659 */
660
661 static void ip_free(struct ipq *qp)
/* */
662 {
663 struct ipfrag *fp;
664 struct ipfrag *xp;
665
666 /*
667 * Stop the timer for this entry.
668 */
669
670 del_timer(&qp->timer);
671
672 /* Remove this entry from the "incomplete datagrams" queue. */
673 cli();
674 if (qp->prev == NULL)
675 {
676 ipqueue = qp->next;
677 if (ipqueue != NULL)
678 ipqueue->prev = NULL;
679 }
680 else
681 {
682 qp->prev->next = qp->next;
683 if (qp->next != NULL)
684 qp->next->prev = qp->prev;
685 }
686
687 /* Release all fragment data. */
688
689 fp = qp->fragments;
690 while (fp != NULL)
691 {
692 xp = fp->next;
693 IS_SKB(fp->skb);
694 kfree_skb(fp->skb,FREE_READ);
695 kfree_s(fp, sizeof(struct ipfrag));
696 fp = xp;
697 }
698
699 /* Release the MAC header. */
700 kfree_s(qp->mac, qp->maclen);
701
702 /* Release the IP header. */
703 kfree_s(qp->iph, qp->ihlen + 8);
704
705 /* Finally, release the queue descriptor itself. */
706 kfree_s(qp, sizeof(struct ipq));
707 sti();
708 }
709
710
711 /*
712 * Oops- a fragment queue timed out. Kill it and send an ICMP reply.
713 */
714
715 static void ip_expire(unsigned long arg)
/* */
716 {
717 struct ipq *qp;
718
719 qp = (struct ipq *)arg;
720
721 /*
722 * Send an ICMP "Fragment Reassembly Timeout" message.
723 */
724
725 ip_statistics.IpReasmTimeout++;
726 ip_statistics.IpReasmFails++;
727 /* This if is always true... shrug */
728 if(qp->fragments!=NULL)
729 icmp_send(qp->fragments->skb,ICMP_TIME_EXCEEDED,
730 ICMP_EXC_FRAGTIME, qp->dev);
731
732 /*
733 * Nuke the fragment queue.
734 */
735 ip_free(qp);
736 }
737
738
739 /*
740 * Add an entry to the 'ipq' queue for a newly received IP datagram.
741 * We will (hopefully :-) receive all other fragments of this datagram
742 * in time, so we just create a queue for this datagram, in which we
743 * will insert the received fragments at their respective positions.
744 */
745
746 static struct ipq *ip_create(struct sk_buff *skb, struct iphdr *iph, struct device *dev)
/* */
747 {
748 struct ipq *qp;
749 int maclen;
750 int ihlen;
751
752 qp = (struct ipq *) kmalloc(sizeof(struct ipq), GFP_ATOMIC);
753 if (qp == NULL)
754 {
755 printk("IP: create: no memory left !\n");
756 return(NULL);
757 skb->dev = qp->dev;
758 }
759 memset(qp, 0, sizeof(struct ipq));
760
761 /*
762 * Allocate memory for the MAC header.
763 *
764 * FIXME: We have a maximum MAC address size limit and define
765 * elsewhere. We should use it here and avoid the 3 kmalloc() calls
766 */
767
768 maclen = ((unsigned long) iph) - ((unsigned long) skb->data);
769 qp->mac = (unsigned char *) kmalloc(maclen, GFP_ATOMIC);
770 if (qp->mac == NULL)
771 {
772 printk("IP: create: no memory left !\n");
773 kfree_s(qp, sizeof(struct ipq));
774 return(NULL);
775 }
776
777 /*
778 * Allocate memory for the IP header (plus 8 octets for ICMP).
779 */
780
781 ihlen = (iph->ihl * sizeof(unsigned long));
782 qp->iph = (struct iphdr *) kmalloc(ihlen + 8, GFP_ATOMIC);
783 if (qp->iph == NULL)
784 {
785 printk("IP: create: no memory left !\n");
786 kfree_s(qp->mac, maclen);
787 kfree_s(qp, sizeof(struct ipq));
788 return(NULL);
789 }
790
791 /* Fill in the structure. */
792 memcpy(qp->mac, skb->data, maclen);
793 memcpy(qp->iph, iph, ihlen + 8);
794 qp->len = 0;
795 qp->ihlen = ihlen;
796 qp->maclen = maclen;
797 qp->fragments = NULL;
798 qp->dev = dev;
799
800 /* Start a timer for this entry. */
801 qp->timer.expires = IP_FRAG_TIME; /* about 30 seconds */
802 qp->timer.data = (unsigned long) qp; /* pointer to queue */
803 qp->timer.function = ip_expire; /* expire function */
804 add_timer(&qp->timer);
805
806 /* Add this entry to the queue. */
807 qp->prev = NULL;
808 cli();
809 qp->next = ipqueue;
810 if (qp->next != NULL)
811 qp->next->prev = qp;
812 ipqueue = qp;
813 sti();
814 return(qp);
815 }
816
817
818 /*
819 * See if a fragment queue is complete.
820 */
821
822 static int ip_done(struct ipq *qp)
/* */
823 {
824 struct ipfrag *fp;
825 int offset;
826
827 /* Only possible if we received the final fragment. */
828 if (qp->len == 0)
829 return(0);
830
831 /* Check all fragment offsets to see if they connect. */
832 fp = qp->fragments;
833 offset = 0;
834 while (fp != NULL)
835 {
836 if (fp->offset > offset)
837 return(0); /* fragment(s) missing */
838 offset = fp->end;
839 fp = fp->next;
840 }
841
842 /* All fragments are present. */
843 return(1);
844 }
845
846
847 /*
848 * Build a new IP datagram from all its fragments.
849 *
850 * FIXME: We copy here because we lack an effective way of handling lists
851 * of bits on input. Until the new skb data handling is in I'm not going
852 * to touch this with a bargepole. This also causes a 4Kish limit on
853 * packet sizes.
854 */
855
856 static struct sk_buff *ip_glue(struct ipq *qp)
/* */
857 {
858 struct sk_buff *skb;
859 struct iphdr *iph;
860 struct ipfrag *fp;
861 unsigned char *ptr;
862 int count, len;
863
864 /*
865 * Allocate a new buffer for the datagram.
866 */
867
868 len = qp->maclen + qp->ihlen + qp->len;
869
870 if ((skb = alloc_skb(len,GFP_ATOMIC)) == NULL)
871 {
872 ip_statistics.IpReasmFails++;
873 printk("IP: queue_glue: no memory for gluing queue 0x%X\n", (int) qp);
874 ip_free(qp);
875 return(NULL);
876 }
877
878 /* Fill in the basic details. */
879 skb->len = (len - qp->maclen);
880 skb->h.raw = skb->data;
881 skb->free = 1;
882
883 /* Copy the original MAC and IP headers into the new buffer. */
884 ptr = (unsigned char *) skb->h.raw;
885 memcpy(ptr, ((unsigned char *) qp->mac), qp->maclen);
886 ptr += qp->maclen;
887 memcpy(ptr, ((unsigned char *) qp->iph), qp->ihlen);
888 ptr += qp->ihlen;
889 skb->h.raw += qp->maclen;
890
891 count = 0;
892
893 /* Copy the data portions of all fragments into the new buffer. */
894 fp = qp->fragments;
895 while(fp != NULL)
896 {
897 if(count+fp->len > skb->len)
898 {
899 printk("Invalid fragment list: Fragment over size.\n");
900 ip_free(qp);
901 kfree_skb(skb,FREE_WRITE);
902 ip_statistics.IpReasmFails++;
903 return NULL;
904 }
905 memcpy((ptr + fp->offset), fp->ptr, fp->len);
906 count += fp->len;
907 fp = fp->next;
908 }
909
910 /* We glued together all fragments, so remove the queue entry. */
911 ip_free(qp);
912
913 /* Done with all fragments. Fixup the new IP header. */
914 iph = skb->h.iph;
915 iph->frag_off = 0;
916 iph->tot_len = htons((iph->ihl * sizeof(unsigned long)) + count);
917 skb->ip_hdr = iph;
918
919 ip_statistics.IpReasmOKs++;
920 return(skb);
921 }
922
923
924 /*
925 * Process an incoming IP datagram fragment.
926 */
927
928 static struct sk_buff *ip_defrag(struct iphdr *iph, struct sk_buff *skb, struct device *dev)
/* */
929 {
930 struct ipfrag *prev, *next;
931 struct ipfrag *tfp;
932 struct ipq *qp;
933 struct sk_buff *skb2;
934 unsigned char *ptr;
935 int flags, offset;
936 int i, ihl, end;
937
938 ip_statistics.IpReasmReqds++;
939
940 /* Find the entry of this IP datagram in the "incomplete datagrams" queue. */
941 qp = ip_find(iph);
942
943 /* Is this a non-fragmented datagram? */
944 offset = ntohs(iph->frag_off);
945 flags = offset & ~IP_OFFSET;
946 offset &= IP_OFFSET;
947 if (((flags & IP_MF) == 0) && (offset == 0))
948 {
949 if (qp != NULL)
950 ip_free(qp); /* Huh? How could this exist?? */
951 return(skb);
952 }
953
954 offset <<= 3; /* offset is in 8-byte chunks */
955
956 /*
957 * If the queue already existed, keep restarting its timer as long
958 * as we still are receiving fragments. Otherwise, create a fresh
959 * queue entry.
960 */
961
962 if (qp != NULL)
963 {
964 del_timer(&qp->timer);
965 qp->timer.expires = IP_FRAG_TIME; /* about 30 seconds */
966 qp->timer.data = (unsigned long) qp; /* pointer to queue */
967 qp->timer.function = ip_expire; /* expire function */
968 add_timer(&qp->timer);
969 }
970 else
971 {
972 /*
973 * If we failed to create it, then discard the frame
974 */
975 if ((qp = ip_create(skb, iph, dev)) == NULL)
976 {
977 skb->sk = NULL;
978 kfree_skb(skb, FREE_READ);
979 ip_statistics.IpReasmFails++;
980 return NULL;
981 }
982 }
983
984 /*
985 * Determine the position of this fragment.
986 */
987
988 ihl = (iph->ihl * sizeof(unsigned long));
989 end = offset + ntohs(iph->tot_len) - ihl;
990
991 /*
992 * Point into the IP datagram 'data' part.
993 */
994
995 ptr = skb->data + dev->hard_header_len + ihl;
996
997 /*
998 * Is this the final fragment?
999 */
1000
1001 if ((flags & IP_MF) == 0)
1002 qp->len = end;
1003
1004 /*
1005 * Find out which fragments are in front and at the back of us
1006 * in the chain of fragments so far. We must know where to put
1007 * this fragment, right?
1008 */
1009
1010 prev = NULL;
1011 for(next = qp->fragments; next != NULL; next = next->next)
1012 {
1013 if (next->offset > offset)
1014 break; /* bingo! */
1015 prev = next;
1016 }
1017
1018 /*
1019 * We found where to put this one.
1020 * Check for overlap with preceding fragment, and, if needed,
1021 * align things so that any overlaps are eliminated.
1022 */
1023 if (prev != NULL && offset < prev->end)
1024 {
1025 i = prev->end - offset;
1026 offset += i; /* ptr into datagram */
1027 ptr += i; /* ptr into fragment data */
1028 }
1029
1030 /*
1031 * Look for overlap with succeeding segments.
1032 * If we can merge fragments, do it.
1033 */
1034
1035 for(; next != NULL; next = tfp)
1036 {
1037 tfp = next->next;
1038 if (next->offset >= end)
1039 break; /* no overlaps at all */
1040
1041 i = end - next->offset; /* overlap is 'i' bytes */
1042 next->len -= i; /* so reduce size of */
1043 next->offset += i; /* next fragment */
1044 next->ptr += i;
1045
1046 /*
1047 * If we get a frag size of <= 0, remove it and the packet
1048 * that it goes with.
1049 */
1050 if (next->len <= 0)
1051 {
1052 if (next->prev != NULL)
1053 next->prev->next = next->next;
1054 else
1055 qp->fragments = next->next;
1056
1057 if (tfp->next != NULL)
1058 next->next->prev = next->prev;
1059
1060 kfree_skb(next->skb,FREE_READ);
1061 kfree_s(next, sizeof(struct ipfrag));
1062 }
1063 }
1064
1065 /*
1066 * Insert this fragment in the chain of fragments.
1067 */
1068
1069 tfp = NULL;
1070 tfp = ip_frag_create(offset, end, skb, ptr);
1071
1072 /*
1073 * No memory to save the fragment - so throw the lot
1074 */
1075
1076 if (!tfp)
1077 {
1078 skb->sk = NULL;
1079 kfree_skb(skb, FREE_READ);
1080 return NULL;
1081 }
1082 tfp->prev = prev;
1083 tfp->next = next;
1084 if (prev != NULL)
1085 prev->next = tfp;
1086 else
1087 qp->fragments = tfp;
1088
1089 if (next != NULL)
1090 next->prev = tfp;
1091
1092 /*
1093 * OK, so we inserted this new fragment into the chain.
1094 * Check if we now have a full IP datagram which we can
1095 * bump up to the IP layer...
1096 */
1097
1098 if (ip_done(qp))
1099 {
1100 skb2 = ip_glue(qp); /* glue together the fragments */
1101 return(skb2);
1102 }
1103 return(NULL);
1104 }
1105
1106
1107 /*
1108 * This IP datagram is too large to be sent in one piece. Break it up into
1109 * smaller pieces (each of size equal to the MAC header plus IP header plus
1110 * a block of the data of the original IP data part) that will yet fit in a
1111 * single device frame, and queue such a frame for sending by calling the
1112 * ip_queue_xmit(). Note that this is recursion, and bad things will happen
1113 * if this function causes a loop...
1114 *
1115 * Yes this is inefficient, feel free to submit a quicker one.
1116 *
1117 * **Protocol Violation**
1118 * We copy all the options to each fragment. !FIXME!
1119 */
1120 void ip_fragment(struct sock *sk, struct sk_buff *skb, struct device *dev, int is_frag)
/* */
1121 {
1122 struct iphdr *iph;
1123 unsigned char *raw;
1124 unsigned char *ptr;
1125 struct sk_buff *skb2;
1126 int left, mtu, hlen, len;
1127 int offset;
1128 unsigned long flags;
1129
1130 /*
1131 * Point into the IP datagram header.
1132 */
1133
1134 raw = skb->data;
1135 iph = (struct iphdr *) (raw + dev->hard_header_len);
1136
1137 skb->ip_hdr = iph;
1138
1139 /*
1140 * Setup starting values.
1141 */
1142
1143 hlen = (iph->ihl * sizeof(unsigned long));
1144 left = ntohs(iph->tot_len) - hlen; /* Space per frame */
1145 hlen += dev->hard_header_len; /* Total header size */
1146 mtu = (dev->mtu - hlen); /* Size of data space */
1147 ptr = (raw + hlen); /* Where to start from */
1148
1149 /*
1150 * Check for any "DF" flag. [DF means do not fragment]
1151 */
1152
1153 if (ntohs(iph->frag_off) & IP_DF)
1154 {
1155 ip_statistics.IpFragFails++;
1156 icmp_send(skb,ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, dev);
1157 return;
1158 }
1159
1160 /*
1161 * The protocol doesn't seem to say what to do in the case that the
1162 * frame + options doesn't fit the mtu. As it used to fall down dead
1163 * in this case we were fortunate it didn't happen
1164 */
1165
1166 if(mtu<8)
1167 {
1168 /* It's wrong but its better than nothing */
1169 icmp_send(skb,ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED,dev);
1170 ip_statistics.IpFragFails++;
1171 return;
1172 }
1173
1174 /*
1175 * Fragment the datagram.
1176 */
1177
1178 /*
1179 * The initial offset is 0 for a complete frame. When
1180 * fragmenting fragments its wherever this one starts.
1181 */
1182
1183 if (is_frag & 2)
1184 offset = (ntohs(iph->frag_off) & 0x1fff) << 3;
1185 else
1186 offset = 0;
1187
1188
1189 /*
1190 * Keep copying data until we run out.
1191 */
1192
1193 while(left > 0)
1194 {
1195 len = left;
1196 /* IF: it doesn't fit, use 'mtu' - the data space left */
1197 if (len > mtu)
1198 len = mtu;
1199 /* IF: we are not sending upto and including the packet end
1200 then align the next start on an eight byte boundary */
1201 if (len < left)
1202 {
1203 len/=8;
1204 len*=8;
1205 }
1206 /*
1207 * Allocate buffer.
1208 */
1209
1210 if ((skb2 = alloc_skb(len + hlen,GFP_ATOMIC)) == NULL)
1211 {
1212 printk("IP: frag: no memory for new fragment!\n");
1213 ip_statistics.IpFragFails++;
1214 return;
1215 }
1216
1217 /*
1218 * Set up data on packet
1219 */
1220
1221 skb2->arp = skb->arp;
1222 if(skb->free==0)
1223 printk("IP fragmenter: BUG free!=1 in fragmenter\n");
1224 skb2->free = 1;
1225 skb2->len = len + hlen;
1226 skb2->h.raw=(char *) skb2->data;
1227 /*
1228 * Charge the memory for the fragment to any owner
1229 * it might possess
1230 */
1231
1232 save_flags(flags);
1233 if (sk)
1234 {
1235 cli();
1236 sk->wmem_alloc += skb2->mem_len;
1237 skb2->sk=sk;
1238 }
1239 restore_flags(flags);
1240 skb2->raddr = skb->raddr; /* For rebuild_header - must be here */
1241
1242 /*
1243 * Copy the packet header into the new buffer.
1244 */
1245
1246 memcpy(skb2->h.raw, raw, hlen);
1247
1248 /*
1249 * Copy a block of the IP datagram.
1250 */
1251 memcpy(skb2->h.raw + hlen, ptr, len);
1252 left -= len;
1253
1254 skb2->h.raw+=dev->hard_header_len;
1255
1256 /*
1257 * Fill in the new header fields.
1258 */
1259 iph = (struct iphdr *)(skb2->h.raw/*+dev->hard_header_len*/);
1260 iph->frag_off = htons((offset >> 3));
1261 /*
1262 * Added AC : If we are fragmenting a fragment thats not the
1263 * last fragment then keep MF on each bit
1264 */
1265 if (left > 0 || (is_frag & 1))
1266 iph->frag_off |= htons(IP_MF);
1267 ptr += len;
1268 offset += len;
1269
1270 /*
1271 * Put this fragment into the sending queue.
1272 */
1273
1274 ip_statistics.IpFragCreates++;
1275
1276 ip_queue_xmit(sk, dev, skb2, 2);
1277 }
1278 ip_statistics.IpFragOKs++;
1279 }
1280
1281
1282
1283 #ifdef CONFIG_IP_FORWARD
1284
1285 /*
1286 * Forward an IP datagram to its next destination.
1287 */
1288
1289 static void ip_forward(struct sk_buff *skb, struct device *dev, int is_frag)
/* */
1290 {
1291 struct device *dev2; /* Output device */
1292 struct iphdr *iph; /* Our header */
1293 struct sk_buff *skb2; /* Output packet */
1294 struct rtable *rt; /* Route we use */
1295 unsigned char *ptr; /* Data pointer */
1296 unsigned long raddr; /* Router IP address */
1297
1298 /*
1299 * See if we are allowed to forward this.
1300 */
1301
1302 #ifdef CONFIG_IP_FIREWALL
1303 if(!ip_fw_chk(skb->h.iph, ip_fw_fwd_chain))
1304 {
1305 return;
1306 }
1307 #endif
1308 /*
1309 * According to the RFC, we must first decrease the TTL field. If
1310 * that reaches zero, we must reply an ICMP control message telling
1311 * that the packet's lifetime expired.
1312 *
1313 * Exception:
1314 * We may not generate an ICMP for an ICMP. icmp_send does the
1315 * enforcement of this so we can forget it here. It is however
1316 * sometimes VERY important.
1317 */
1318
1319 iph = skb->h.iph;
1320 iph->ttl--;
1321 if (iph->ttl <= 0)
1322 {
1323 /* Tell the sender its packet died... */
1324 icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, dev);
1325 return;
1326 }
1327
1328 /*
1329 * Re-compute the IP header checksum.
1330 * This is inefficient. We know what has happened to the header
1331 * and could thus adjust the checksum as Phil Karn does in KA9Q
1332 */
1333
1334 ip_send_check(iph);
1335
1336 /*
1337 * OK, the packet is still valid. Fetch its destination address,
1338 * and give it to the IP sender for further processing.
1339 */
1340
1341 rt = ip_rt_route(iph->daddr, NULL, NULL);
1342 if (rt == NULL)
1343 {
1344 /*
1345 * Tell the sender its packet cannot be delivered. Again
1346 * ICMP is screened later.
1347 */
1348 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_UNREACH, dev);
1349 return;
1350 }
1351
1352
1353 /*
1354 * Gosh. Not only is the packet valid; we even know how to
1355 * forward it onto its final destination. Can we say this
1356 * is being plain lucky?
1357 * If the router told us that there is no GW, use the dest.
1358 * IP address itself- we seem to be connected directly...
1359 */
1360
1361 raddr = rt->rt_gateway;
1362
1363 if (raddr != 0)
1364 {
1365 /*
1366 * There is a gateway so find the correct route for it.
1367 * Gateways cannot in turn be gatewayed.
1368 */
1369 rt = ip_rt_route(raddr, NULL, NULL);
1370 if (rt == NULL)
1371 {
1372 /*
1373 * Tell the sender its packet cannot be delivered...
1374 */
1375 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, dev);
1376 return;
1377 }
1378 if (rt->rt_gateway != 0)
1379 raddr = rt->rt_gateway;
1380 }
1381 else
1382 raddr = iph->daddr;
1383
1384 /*
1385 * Having picked a route we can now send the frame out.
1386 */
1387
1388 dev2 = rt->rt_dev;
1389
1390 /*
1391 * In IP you never forward a frame on the interface that it arrived
1392 * upon. We should generate an ICMP HOST REDIRECT giving the route
1393 * we calculated.
1394 * For now just dropping the packet is an acceptable compromise.
1395 */
1396
1397 if (dev == dev2)
1398 return;
1399
1400 /*
1401 * We now allocate a new buffer, and copy the datagram into it.
1402 * If the indicated interface is up and running, kick it.
1403 */
1404
1405 if (dev2->flags & IFF_UP)
1406 {
1407
1408 /*
1409 * Current design decrees we copy the packet. For identical header
1410 * lengths we could avoid it. The new skb code will let us push
1411 * data so the problem goes away then.
1412 */
1413
1414 skb2 = alloc_skb(dev2->hard_header_len + skb->len, GFP_ATOMIC);
1415 /*
1416 * This is rare and since IP is tolerant of network failures
1417 * quite harmless.
1418 */
1419 if (skb2 == NULL)
1420 {
1421 printk("\nIP: No memory available for IP forward\n");
1422 return;
1423 }
1424 ptr = skb2->data;
1425 skb2->free = 1;
1426 skb2->len = skb->len + dev2->hard_header_len;
1427 skb2->h.raw = ptr;
1428
1429 /*
1430 * Copy the packet data into the new buffer.
1431 */
1432 memcpy(ptr + dev2->hard_header_len, skb->h.raw, skb->len);
1433
1434 /* Now build the MAC header. */
1435 (void) ip_send(skb2, raddr, skb->len, dev2, dev2->pa_addr);
1436
1437 ip_statistics.IpForwDatagrams++;
1438
1439 /*
1440 * See if it needs fragmenting. Note in ip_rcv we tagged
1441 * the fragment type. This must be right so that
1442 * the fragmenter does the right thing.
1443 */
1444
1445 if(skb2->len > dev2->mtu + dev2->hard_header_len)
1446 {
1447 ip_fragment(NULL,skb2,dev2, is_frag);
1448 kfree_skb(skb2,FREE_WRITE);
1449 }
1450 else
1451 {
1452 #ifdef CONFIG_IP_ACCT
1453 /*
1454 * Count mapping we shortcut
1455 */
1456
1457 ip_acct_cnt(iph,ip_acct_chain,1);
1458 #endif
1459
1460 /*
1461 * Map service types to priority. We lie about
1462 * throughput being low priority, but its a good
1463 * choice to help improve general usage.
1464 */
1465 if(iph->tos & IPTOS_LOWDELAY)
1466 dev_queue_xmit(skb2, dev2, SOPRI_INTERACTIVE);
1467 else if(iph->tos & IPTOS_THROUGHPUT)
1468 dev_queue_xmit(skb2, dev2, SOPRI_BACKGROUND);
1469 else
1470 dev_queue_xmit(skb2, dev2, SOPRI_NORMAL);
1471 }
1472 }
1473 }
1474
1475
1476 #endif
1477
1478 /*
1479 * This function receives all incoming IP datagrams.
1480 */
1481
1482 int ip_rcv(struct sk_buff *skb, struct device *dev, struct packet_type *pt)
/* */
1483 {
1484 struct iphdr *iph = skb->h.iph;
1485 struct sock *raw_sk=NULL;
1486 unsigned char hash;
1487 unsigned char flag = 0;
1488 unsigned char opts_p = 0; /* Set iff the packet has options. */
1489 struct inet_protocol *ipprot;
1490 static struct options opt; /* since we don't use these yet, and they
1491 take up stack space. */
1492 int brd=IS_MYADDR;
1493 int is_frag=0;
1494
1495 ip_statistics.IpInReceives++;
1496
1497 /*
1498 * Tag the ip header of this packet so we can find it
1499 */
1500
1501 skb->ip_hdr = iph;
1502
1503 /*
1504 * Is the datagram acceptable?
1505 *
1506 * 1. Length at least the size of an ip header
1507 * 2. Version of 4
1508 * 3. Checksums correctly. [Speed optimisation for later, skip loopback checksums]
1509 * (4. We ought to check for IP multicast addresses and undefined types.. does this matter ?)
1510 */
1511
1512 if (skb->len<sizeof(struct iphdr) || iph->ihl<5 || iph->version != 4 || ip_fast_csum((unsigned char *)iph, iph->ihl) !=0)
1513 {
1514 ip_statistics.IpInHdrErrors++;
1515 kfree_skb(skb, FREE_WRITE);
1516 return(0);
1517 }
1518
1519 /*
1520 * See if the firewall wants to dispose of the packet.
1521 */
1522
1523 #ifdef CONFIG_IP_FIREWALL
1524
1525 if(!LOOPBACK(iph->daddr) && !ip_fw_chk(iph,ip_fw_blk_chain))
1526 {
1527 kfree_skb(skb, FREE_WRITE);
1528 return 0;
1529 }
1530
1531 #endif
1532
1533 /*
1534 * Our transport medium may have padded the buffer out. Now we know it
1535 * is IP we can trim to the true length of the frame.
1536 */
1537
1538 skb->len=ntohs(iph->tot_len);
1539
1540 /*
1541 * Next analyse the packet for options. Studies show under one packet in
1542 * a thousand have options....
1543 */
1544
1545 if (iph->ihl != 5)
1546 { /* Fast path for the typical optionless IP packet. */
1547 memset((char *) &opt, 0, sizeof(opt));
1548 if (do_options(iph, &opt) != 0)
1549 return 0;
1550 opts_p = 1;
1551 }
1552
1553 /*
1554 * Remember if the frame is fragmented.
1555 */
1556
1557 if(iph->frag_off)
1558 {
1559 if (iph->frag_off & 0x0020)
1560 is_frag|=1;
1561 /*
1562 * Last fragment ?
1563 */
1564
1565 if (ntohs(iph->frag_off) & 0x1fff)
1566 is_frag|=2;
1567 }
1568
1569 /*
1570 * Do any IP forwarding required. chk_addr() is expensive -- avoid it someday.
1571 *
1572 * This is inefficient. While finding out if it is for us we could also compute
1573 * the routing table entry. This is where the great unified cache theory comes
1574 * in as and when someone implements it
1575 *
1576 * For most hosts over 99% of packets match the first conditional
1577 * and don't go via ip_chk_addr. Note: brd is set to IS_MYADDR at
1578 * function entry.
1579 */
1580
1581 if ( iph->daddr != skb->dev->pa_addr && (brd = ip_chk_addr(iph->daddr)) == 0)
1582 {
1583 /*
1584 * Don't forward multicast or broadcast frames.
1585 */
1586
1587 if(skb->pkt_type!=PACKET_HOST || brd==IS_BROADCAST)
1588 {
1589 kfree_skb(skb,FREE_WRITE);
1590 return 0;
1591 }
1592
1593 /*
1594 * The packet is for another target. Forward the frame
1595 */
1596
1597 #ifdef CONFIG_IP_FORWARD
1598 ip_forward(skb, dev, is_frag);
1599 #else
1600 /* printk("Machine %lx tried to use us as a forwarder to %lx but we have forwarding disabled!\n",
1601 iph->saddr,iph->daddr);*/
1602 ip_statistics.IpInAddrErrors++;
1603 #endif
1604 /*
1605 * The forwarder is inefficient and copies the packet. We
1606 * free the original now.
1607 */
1608
1609 kfree_skb(skb, FREE_WRITE);
1610 return(0);
1611 }
1612
1613 #ifdef CONFIG_IP_MULTICAST
1614
1615 if(brd==IS_MULTICAST && iph->daddr!=IGMP_ALL_HOSTS && !(dev->flags&IFF_LOOPBACK))
1616 {
1617 /*
1618 * Check it is for one of our groups
1619 */
1620 struct ip_mc_list *ip_mc=dev->ip_mc_list;
1621 do
1622 {
1623 if(ip_mc==NULL)
1624 {
1625 kfree_skb(skb, FREE_WRITE);
1626 return 0;
1627 }
1628 if(ip_mc->multiaddr==iph->daddr)
1629 break;
1630 ip_mc=ip_mc->next;
1631 }
1632 while(1);
1633 }
1634 #endif
1635 /*
1636 * Account for the packet
1637 */
1638
1639 #ifdef CONFIG_IP_ACCT
1640 ip_acct_cnt(iph,ip_acct_chain,1);
1641 #endif
1642
1643 /*
1644 * Reassemble IP fragments.
1645 */
1646
1647 if(is_frag)
1648 {
1649 /* Defragment. Obtain the complete packet if there is one */
1650 skb=ip_defrag(iph,skb,dev);
1651 if(skb==NULL)
1652 return 0;
1653 skb->dev = dev;
1654 iph=skb->h.iph;
1655 }
1656
1657
1658
1659 /*
1660 * Point into the IP datagram, just past the header.
1661 */
1662
1663 skb->ip_hdr = iph;
1664 skb->h.raw += iph->ihl*4;
1665
1666 /*
1667 * Deliver to raw sockets. This is fun as to avoid copies we want to make no surplus copies.
1668 */
1669
1670 hash = iph->protocol & (SOCK_ARRAY_SIZE-1);
1671
1672 /* If there maybe a raw socket we must check - if not we don't care less */
1673 if((raw_sk=raw_prot.sock_array[hash])!=NULL)
1674 {
1675 struct sock *sknext=NULL;
1676 struct sk_buff *skb1;
1677 raw_sk=get_sock_raw(raw_sk, hash, iph->saddr, iph->daddr);
1678 if(raw_sk) /* Any raw sockets */
1679 {
1680 do
1681 {
1682 /* Find the next */
1683 sknext=get_sock_raw(raw_sk->next, hash, iph->saddr, iph->daddr);
1684 if(sknext)
1685 skb1=skb_clone(skb, GFP_ATOMIC);
1686 else
1687 break; /* One pending raw socket left */
1688 if(skb1)
1689 raw_rcv(raw_sk, skb1, dev, iph->saddr,iph->daddr);
1690 raw_sk=sknext;
1691 }
1692 while(raw_sk!=NULL);
1693 /* Here either raw_sk is the last raw socket, or NULL if none */
1694 /* We deliver to the last raw socket AFTER the protocol checks as it avoids a surplus copy */
1695 }
1696 }
1697
1698 /*
1699 * skb->h.raw now points at the protocol beyond the IP header.
1700 */
1701
1702 hash = iph->protocol & (MAX_INET_PROTOS -1);
1703 for (ipprot = (struct inet_protocol *)inet_protos[hash];ipprot != NULL;ipprot=(struct inet_protocol *)ipprot->next)
1704 {
1705 struct sk_buff *skb2;
1706
1707 if (ipprot->protocol != iph->protocol)
1708 continue;
1709 /*
1710 * See if we need to make a copy of it. This will
1711 * only be set if more than one protocol wants it.
1712 * and then not for the last one. If there is a pending
1713 * raw delivery wait for that
1714 */
1715 if (ipprot->copy || raw_sk)
1716 {
1717 skb2 = skb_clone(skb, GFP_ATOMIC);
1718 if(skb2==NULL)
1719 continue;
1720 }
1721 else
1722 {
1723 skb2 = skb;
1724 }
1725 flag = 1;
1726
1727 /*
1728 * Pass on the datagram to each protocol that wants it,
1729 * based on the datagram protocol. We should really
1730 * check the protocol handler's return values here...
1731 */
1732 ipprot->handler(skb2, dev, opts_p ? &opt : 0, iph->daddr,
1733 (ntohs(iph->tot_len) - (iph->ihl * 4)),
1734 iph->saddr, 0, ipprot);
1735
1736 }
1737
1738 /*
1739 * All protocols checked.
1740 * If this packet was a broadcast, we may *not* reply to it, since that
1741 * causes (proven, grin) ARP storms and a leakage of memory (i.e. all
1742 * ICMP reply messages get queued up for transmission...)
1743 */
1744
1745 if(raw_sk!=NULL) /* Shift to last raw user */
1746 raw_rcv(raw_sk, skb, dev, iph->saddr, iph->daddr);
1747 else if (!flag) /* Free and report errors */
1748 {
1749 if (brd != IS_BROADCAST && brd!=IS_MULTICAST)
1750 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PROT_UNREACH, dev);
1751 kfree_skb(skb, FREE_WRITE);
1752 }
1753
1754 return(0);
1755 }
1756
1757 /*
1758 * Loop a packet back to the sender.
1759 */
1760
1761 static void ip_loopback(struct device *old_dev, struct sk_buff *skb)
/* */
1762 {
1763 extern struct device loopback_dev;
1764 struct device *dev=&loopback_dev;
1765 int len=skb->len-old_dev->hard_header_len;
1766 struct sk_buff *newskb=alloc_skb(len+dev->hard_header_len, GFP_ATOMIC);
1767
1768 if(newskb==NULL)
1769 return;
1770
1771 newskb->link3=NULL;
1772 newskb->sk=NULL;
1773 newskb->dev=dev;
1774 newskb->saddr=skb->saddr;
1775 newskb->daddr=skb->daddr;
1776 newskb->raddr=skb->raddr;
1777 newskb->free=1;
1778 newskb->lock=0;
1779 newskb->users=0;
1780 newskb->pkt_type=skb->pkt_type;
1781 newskb->len=len+dev->hard_header_len;
1782
1783
1784 newskb->ip_hdr=(struct iphdr *)(newskb->data+ip_send(newskb, skb->ip_hdr->daddr, len, dev, skb->ip_hdr->saddr));
1785 memcpy(newskb->ip_hdr,skb->ip_hdr,len);
1786
1787 /* Recurse. The device check against IFF_LOOPBACK will stop infinite recursion */
1788
1789 /*printk("Loopback output queued [%lX to %lX].\n", newskb->ip_hdr->saddr,newskb->ip_hdr->daddr);*/
1790 ip_queue_xmit(NULL, dev, newskb, 1);
1791 }
1792
1793
1794 /*
1795 * Queues a packet to be sent, and starts the transmitter
1796 * if necessary. if free = 1 then we free the block after
1797 * transmit, otherwise we don't. If free==2 we not only
1798 * free the block but also don't assign a new ip seq number.
1799 * This routine also needs to put in the total length,
1800 * and compute the checksum
1801 */
1802
1803 void ip_queue_xmit(struct sock *sk, struct device *dev,
/* */
1804 struct sk_buff *skb, int free)
1805 {
1806 struct iphdr *iph;
1807 unsigned char *ptr;
1808
1809 /* Sanity check */
1810 if (dev == NULL)
1811 {
1812 printk("IP: ip_queue_xmit dev = NULL\n");
1813 return;
1814 }
1815
1816 IS_SKB(skb);
1817
1818 /*
1819 * Do some book-keeping in the packet for later
1820 */
1821
1822
1823 skb->dev = dev;
1824 skb->when = jiffies;
1825
1826 /*
1827 * Find the IP header and set the length. This is bad
1828 * but once we get the skb data handling code in the
1829 * hardware will push its header sensibly and we will
1830 * set skb->ip_hdr to avoid this mess and the fixed
1831 * header length problem
1832 */
1833
1834 ptr = skb->data;
1835 ptr += dev->hard_header_len;
1836 iph = (struct iphdr *)ptr;
1837 skb->ip_hdr = iph;
1838 iph->tot_len = ntohs(skb->len-dev->hard_header_len);
1839
1840 /*
1841 * No reassigning numbers to fragments...
1842 */
1843
1844 if(free!=2)
1845 iph->id = htons(ip_id_count++);
1846 else
1847 free=1;
1848
1849 /* All buffers without an owner socket get freed */
1850 if (sk == NULL)
1851 free = 1;
1852
1853 skb->free = free;
1854
1855 /*
1856 * Do we need to fragment. Again this is inefficient.
1857 * We need to somehow lock the original buffer and use
1858 * bits of it.
1859 */
1860
1861 if(skb->len > dev->mtu + dev->hard_header_len)
1862 {
1863 ip_fragment(sk,skb,dev,0);
1864 IS_SKB(skb);
1865 kfree_skb(skb,FREE_WRITE);
1866 return;
1867 }
1868
1869 /*
1870 * Add an IP checksum
1871 */
1872
1873 ip_send_check(iph);
1874
1875 /*
1876 * Print the frame when debugging
1877 */
1878
1879 /*
1880 * More debugging. You cannot queue a packet already on a list
1881 * Spot this and moan loudly.
1882 */
1883 if (skb->next != NULL)
1884 {
1885 printk("ip_queue_xmit: next != NULL\n");
1886 skb_unlink(skb);
1887 }
1888
1889 /*
1890 * If a sender wishes the packet to remain unfreed
1891 * we add it to his send queue. This arguably belongs
1892 * in the TCP level since nobody else uses it. BUT
1893 * remember IPng might change all the rules.
1894 */
1895
1896 if (!free)
1897 {
1898 unsigned long flags;
1899 /* The socket now has more outstanding blocks */
1900
1901 sk->packets_out++;
1902
1903 /* Protect the list for a moment */
1904 save_flags(flags);
1905 cli();
1906
1907 if (skb->link3 != NULL)
1908 {
1909 printk("ip.c: link3 != NULL\n");
1910 skb->link3 = NULL;
1911 }
1912 if (sk->send_head == NULL)
1913 {
1914 sk->send_tail = skb;
1915 sk->send_head = skb;
1916 }
1917 else
1918 {
1919 sk->send_tail->link3 = skb;
1920 sk->send_tail = skb;
1921 }
1922 /* skb->link3 is NULL */
1923
1924 /* Interrupt restore */
1925 restore_flags(flags);
1926 /* Set the IP write timeout to the round trip time for the packet.
1927 If an acknowledge has not arrived by then we may wish to act */
1928 reset_timer(sk, TIME_WRITE, sk->rto);
1929 }
1930 else
1931 /* Remember who owns the buffer */
1932 skb->sk = sk;
1933
1934 /*
1935 * If the indicated interface is up and running, send the packet.
1936 */
1937
1938 ip_statistics.IpOutRequests++;
1939 #ifdef CONFIG_IP_ACCT
1940 ip_acct_cnt(iph,ip_acct_chain,1);
1941 #endif
1942
1943 #ifdef CONFIG_IP_MULTICAST
1944
1945 /*
1946 * Multicasts are looped back for other local users
1947 */
1948
1949 if (MULTICAST(iph->daddr) && !(dev->flags&IFF_LOOPBACK))
1950 {
1951 if(sk==NULL || sk->ip_mc_loop)
1952 {
1953 if(skb->daddr==IGMP_ALL_HOSTS)
1954 ip_loopback(dev,skb);
1955 else
1956 {
1957 struct ip_mc_list *imc=dev->ip_mc_list;
1958 while(imc!=NULL)
1959 {
1960 if(imc->multiaddr==iph->daddr)
1961 {
1962 ip_loopback(dev,skb);
1963 break;
1964 }
1965 imc=imc->next;
1966 }
1967 }
1968 }
1969 /* Multicasts with ttl 0 must not go beyond the host */
1970
1971 if(skb->ip_hdr->ttl==0)
1972 {
1973 kfree_skb(skb, FREE_READ);
1974 return;
1975 }
1976 }
1977 #endif
1978 if((dev->flags&IFF_BROADCAST) && iph->daddr==dev->pa_brdaddr && !(dev->flags&IFF_LOOPBACK))
1979 ip_loopback(dev,skb);
1980
1981 if (dev->flags & IFF_UP)
1982 {
1983 /*
1984 * If we have an owner use its priority setting,
1985 * otherwise use NORMAL
1986 */
1987
1988 if (sk != NULL)
1989 {
1990 dev_queue_xmit(skb, dev, sk->priority);
1991 }
1992 else
1993 {
1994 dev_queue_xmit(skb, dev, SOPRI_NORMAL);
1995 }
1996 }
1997 else
1998 {
1999 ip_statistics.IpOutDiscards++;
2000 if (free)
2001 kfree_skb(skb, FREE_WRITE);
2002 }
2003 }
2004
2005
2006
2007 #ifdef CONFIG_IP_MULTICAST
2008
2009 /*
2010 * Write an multicast group list table for the IGMP daemon to
2011 * read.
2012 */
2013
2014 int ip_mc_procinfo(char *buffer, char **start, off_t offset, int length)
/* */
2015 {
2016 off_t pos=0, begin=0;
2017 struct ip_mc_list *im;
2018 unsigned long flags;
2019 int len=0;
2020
2021
2022 len=sprintf(buffer,"Device : Multicast\n");
2023 save_flags(flags);
2024 cli();
2025
2026 im=ip_mc_head;
2027
2028 while(im!=NULL)
2029 {
2030 len+=sprintf(buffer+len,"%-10s: %08lX\n", im->interface->name, im->multiaddr);
2031 pos=begin+len;
2032 if(pos<offset)
2033 {
2034 len=0;
2035 begin=pos;
2036 }
2037 if(pos>offset+length)
2038 break;
2039 im=im->next;
2040 }
2041 restore_flags(flags);
2042 *start=buffer+(offset-begin);
2043 len-=(offset-begin);
2044 if(len>length)
2045 len=length;
2046 return len;
2047 }
2048
2049
2050 #endif
2051 /*
2052 * Socket option code for IP. This is the end of the line after any TCP,UDP etc options on
2053 * an IP socket.
2054 *
2055 * We implement IP_TOS (type of service), IP_TTL (time to live).
2056 *
2057 * Next release we will sort out IP_OPTIONS since for some people are kind of important.
2058 */
2059
2060 int ip_setsockopt(struct sock *sk, int level, int optname, char *optval, int optlen)
/* */
2061 {
2062 int val,err;
2063 #if defined(CONFIG_IP_FIREWALL) || defined(CONFIG_IP_ACCT)
2064 struct ip_fw tmp_fw;
2065 #endif
2066 if (optval == NULL)
2067 return(-EINVAL);
2068
2069 err=verify_area(VERIFY_READ, optval, sizeof(int));
2070 if(err)
2071 return err;
2072
2073 val = get_fs_long((unsigned long *)optval);
2074
2075 if(level!=SOL_IP)
2076 return -EOPNOTSUPP;
2077
2078 #ifdef CONFIG_IP_MULTICAST
2079 if(optname==IP_MULTICAST_TTL)
2080 {
2081 unsigned char ucval;
2082 ucval=get_fs_byte((unsigned char *)optval);
2083 printk("MC TTL %d\n", ucval);
2084 if(ucval<1||ucval>255)
2085 return -EINVAL;
2086 sk->ip_mc_ttl=(int)ucval;
2087 return 0;
2088 }
2089 #endif
2090
2091 switch(optname)
2092 {
2093 case IP_TOS:
2094 if(val<0||val>255)
2095 return -EINVAL;
2096 sk->ip_tos=val;
2097 if(val==IPTOS_LOWDELAY)
2098 sk->priority=SOPRI_INTERACTIVE;
2099 if(val==IPTOS_THROUGHPUT)
2100 sk->priority=SOPRI_BACKGROUND;
2101 return 0;
2102 case IP_TTL:
2103 if(val<1||val>255)
2104 return -EINVAL;
2105 sk->ip_ttl=val;
2106 return 0;
2107 #ifdef CONFIG_IP_MULTICAST
2108 #ifdef GCC_WORKS
2109 case IP_MULTICAST_TTL:
2110 {
2111 unsigned char ucval;
2112
2113 ucval=get_fs_byte((unsigned char *)optval);
2114 printk("MC TTL %d\n", ucval);
2115 if(ucval<1||ucval>255)
2116 return -EINVAL;
2117 sk->ip_mc_ttl=(int)ucval;
2118 return 0;
2119 }
2120 #endif
2121 case IP_MULTICAST_LOOP:
2122 {
2123 unsigned char ucval;
2124
2125 ucval=get_fs_byte((unsigned char *)optval);
2126 if(ucval!=0 && ucval!=1)
2127 return -EINVAL;
2128 sk->ip_mc_loop=(int)ucval;
2129 return 0;
2130 }
2131 case IP_MULTICAST_IF:
2132 {
2133 /* Not fully tested */
2134 struct in_addr addr;
2135 struct device *dev=NULL;
2136
2137 /*
2138 * Check the arguments are allowable
2139 */
2140
2141 err=verify_area(VERIFY_READ, optval, sizeof(addr));
2142 if(err)
2143 return err;
2144
2145 memcpy_fromfs(&addr,optval,sizeof(addr));
2146
2147 printk("MC bind %s\n", in_ntoa(addr.s_addr));
2148
2149 /*
2150 * What address has been requested
2151 */
2152
2153 if(addr.s_addr==INADDR_ANY) /* Default */
2154 {
2155 sk->ip_mc_name[0]=0;
2156 return 0;
2157 }
2158
2159 /*
2160 * Find the device
2161 */
2162
2163 for(dev = dev_base; dev; dev = dev->next)
2164 {
2165 if((dev->flags&IFF_UP)&&(dev->flags&IFF_MULTICAST)&&
2166 (dev->pa_addr==addr.s_addr))
2167 break;
2168 }
2169
2170 /*
2171 * Did we find one
2172 */
2173
2174 if(dev)
2175 {
2176 strcpy(sk->ip_mc_name,dev->name);
2177 return 0;
2178 }
2179 return -EADDRNOTAVAIL;
2180 }
2181
2182 case IP_ADD_MEMBERSHIP:
2183 {
2184
2185 /*
2186 * FIXME: Add/Del membership should have a semaphore protecting them from re-entry
2187 */
2188 struct ip_mreq mreq;
2189 static struct options optmem;
2190 unsigned long route_src;
2191 struct rtable *rt;
2192 struct device *dev=NULL;
2193
2194 /*
2195 * Check the arguments.
2196 */
2197
2198 err=verify_area(VERIFY_READ, optval, sizeof(mreq));
2199 if(err)
2200 return err;
2201
2202 memcpy_fromfs(&mreq,optval,sizeof(mreq));
2203
2204 /*
2205 * Get device for use later
2206 */
2207
2208 if(mreq.imr_interface.s_addr==INADDR_ANY)
2209 {
2210 /*
2211 * Not set so scan.
2212 */
2213 if((rt=ip_rt_route(mreq.imr_multiaddr.s_addr,&optmem, &route_src))!=NULL)
2214 {
2215 dev=rt->rt_dev;
2216 rt->rt_use--;
2217 }
2218 }
2219 else
2220 {
2221 /*
2222 * Find a suitable device.
2223 */
2224 for(dev = dev_base; dev; dev = dev->next)
2225 {
2226 if((dev->flags&IFF_UP)&&(dev->flags&IFF_MULTICAST)&&
2227 (dev->pa_addr==mreq.imr_interface.s_addr))
2228 break;
2229 }
2230 }
2231
2232 /*
2233 * No device, no cookies.
2234 */
2235
2236 if(!dev)
2237 return -ENODEV;
2238
2239 /*
2240 * Join group.
2241 */
2242
2243 return ip_mc_join_group(sk,dev,mreq.imr_multiaddr.s_addr);
2244 }
2245
2246 case IP_DROP_MEMBERSHIP:
2247 {
2248 struct ip_mreq mreq;
2249 struct rtable *rt;
2250 static struct options optmem;
2251 unsigned long route_src;
2252 struct device *dev=NULL;
2253
2254 /*
2255 * Check the arguments
2256 */
2257
2258 err=verify_area(VERIFY_READ, optval, sizeof(mreq));
2259 if(err)
2260 return err;
2261
2262 memcpy_fromfs(&mreq,optval,sizeof(mreq));
2263
2264 /*
2265 * Get device for use later
2266 */
2267
2268 if(mreq.imr_interface.s_addr==INADDR_ANY)
2269 {
2270 if((rt=ip_rt_route(mreq.imr_multiaddr.s_addr,&optmem, &route_src))!=NULL)
2271 {
2272 dev=rt->rt_dev;
2273 rt->rt_use--;
2274 }
2275 }
2276 else
2277 {
2278 for(dev = dev_base; dev; dev = dev->next)
2279 {
2280 if((dev->flags&IFF_UP)&& (dev->flags&IFF_MULTICAST)&&
2281 (dev->pa_addr==mreq.imr_interface.s_addr))
2282 break;
2283 }
2284 }
2285
2286 /*
2287 * Did we find a suitable device.
2288 */
2289
2290 if(!dev)
2291 return -ENODEV;
2292
2293 /*
2294 * Leave group
2295 */
2296
2297 return ip_mc_leave_group(sk,dev,mreq.imr_multiaddr.s_addr);
2298 }
2299 #endif
2300 #ifdef CONFIG_IP_FIREWALL
2301 case IP_FW_ADD_BLK:
2302 case IP_FW_DEL_BLK:
2303 case IP_FW_ADD_FWD:
2304 case IP_FW_DEL_FWD:
2305 case IP_FW_CHK_BLK:
2306 case IP_FW_CHK_FWD:
2307 case IP_FW_FLUSH:
2308 case IP_FW_POLICY:
2309 if(!suser())
2310 return -EPERM;
2311 if(optlen>sizeof(tmp_fw) || optlen<1)
2312 return -EINVAL;
2313 err=verify_area(VERIFY_READ,optval,optlen);
2314 if(err)
2315 return err;
2316 memcpy_fromfs(&tmp_fw,optval,optlen);
2317 err=ip_fw_ctl(optname, &tmp_fw,optlen);
2318 return -err; /* -0 is 0 after all */
2319
2320 #endif
2321 #ifdef CONFIG_IP_ACCT
2322 case IP_ACCT_DEL:
2323 case IP_ACCT_ADD:
2324 case IP_ACCT_FLUSH:
2325 case IP_ACCT_ZERO:
2326 if(!suser())
2327 return -EPERM;
2328 if(optlen>sizeof(tmp_fw) || optlen<1)
2329 return -EINVAL;
2330 err=verify_area(VERIFY_READ,optval,optlen);
2331 if(err)
2332 return err;
2333 memcpy_fromfs(&tmp_fw, optval,optlen);
2334 err=ip_acct_ctl(optname, &tmp_fw,optlen);
2335 return -err; /* -0 is 0 after all */
2336 #endif
2337 /* IP_OPTIONS and friends go here eventually */
2338 default:
2339 return(-ENOPROTOOPT);
2340 }
2341 }
2342
2343 /*
2344 * Get the options. Note for future reference. The GET of IP options gets the
2345 * _received_ ones. The set sets the _sent_ ones.
2346 */
2347
2348 int ip_getsockopt(struct sock *sk, int level, int optname, char *optval, int *optlen)
/* */
2349 {
2350 int val,err;
2351 #ifdef CONFIG_IP_MULTICAST
2352 int len;
2353 #endif
2354
2355 if(level!=SOL_IP)
2356 return -EOPNOTSUPP;
2357
2358 switch(optname)
2359 {
2360 case IP_TOS:
2361 val=sk->ip_tos;
2362 break;
2363 case IP_TTL:
2364 val=sk->ip_ttl;
2365 break;
2366 #ifdef CONFIG_IP_MULTICAST
2367 case IP_MULTICAST_TTL:
2368 val=sk->ip_mc_ttl;
2369 break;
2370 case IP_MULTICAST_LOOP:
2371 val=sk->ip_mc_loop;
2372 break;
2373 case IP_MULTICAST_IF:
2374 err=verify_area(VERIFY_WRITE, optlen, sizeof(int));
2375 if(err)
2376 return err;
2377 len=strlen(sk->ip_mc_name);
2378 err=verify_area(VERIFY_WRITE, optval, len);
2379 if(err)
2380 return err;
2381 put_fs_long(len,(unsigned long *) optlen);
2382 memcpy_tofs((void *)optval,sk->ip_mc_name, len);
2383 return 0;
2384 #endif
2385 default:
2386 return(-ENOPROTOOPT);
2387 }
2388 err=verify_area(VERIFY_WRITE, optlen, sizeof(int));
2389 if(err)
2390 return err;
2391 put_fs_long(sizeof(int),(unsigned long *) optlen);
2392
2393 err=verify_area(VERIFY_WRITE, optval, sizeof(int));
2394 if(err)
2395 return err;
2396 put_fs_long(val,(unsigned long *)optval);
2397
2398 return(0);
2399 }
2400
2401 /*
2402 * IP protocol layer initialiser
2403 */
2404
2405 static struct packet_type ip_packet_type =
2406 {
2407 0, /* MUTTER ntohs(ETH_P_IP),*/
2408 0, /* copy */
2409 ip_rcv,
2410 NULL,
2411 NULL,
2412 };
2413
2414
2415 /*
2416 * IP registers the packet type and then calls the subprotocol initialisers
2417 */
2418
2419 void ip_init(void)
/* ![[last]](../icons/n_last.png)
*/
2420 {
2421 ip_packet_type.type=htons(ETH_P_IP);
2422 dev_add_pack(&ip_packet_type);
2423 /* ip_raw_init();
2424 ip_packet_init();
2425 ip_tcp_init();
2426 ip_udp_init();*/
2427 }
![[bottom]](../icons/n_bottom.png){kind=icon}
*/