net/inet/protocol.c

/* */
This source file includes following definitions.
inet_get_protocol
inet_add_protocol
inet_del_protocol
   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  *              INET protocol dispatch tables.
   7  *
   8  * Version:     @(#)protocol.c  1.0.5   05/25/93
   9  *
  10  * Authors:     Ross Biro, <bir7@leland.Stanford.Edu>
  11  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12  *
  13  * Fixes:
  14  *              Alan Cox        : Ahah! udp icmp errors don't work because
  15  *                                udp_err is never called!
  16  *              Alan Cox        : Added new fields for init and ready for
  17  *                                proper fragmentation (_NO_ 4K limits!)
  18  *
  19  *              This program is free software; you can redistribute it and/or
  20  *              modify it under the terms of the GNU General Public License
  21  *              as published by the Free Software Foundation; either version
  22  *              2 of the License, or (at your option) any later version.
  23  */
  24 #include <asm/segment.h>
  25 #include <asm/system.h>
  26 #include <linux/types.h>
  27 #include <linux/kernel.h>
  28 #include <linux/sched.h>
  29 #include <linux/string.h>
  30 #include <linux/config.h>
  31 #include <linux/socket.h>
  32 #include <linux/in.h>
  33 #include <linux/inet.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/timer.h>
  36 #include "ip.h"
  37 #include "protocol.h"
  38 #include "tcp.h"
  39 #include <linux/skbuff.h>
  40 #include "sock.h"
  41 #include "icmp.h"
  42 #include "udp.h"
  43 #include "igmp.h"
  44 
  45 
  46 static struct inet_protocol tcp_protocol = {
  47   tcp_rcv,              /* TCP handler          */
  48   NULL,                 /* No fragment handler (and won't be for a long time) */
  49   tcp_err,              /* TCP error control    */
  50   NULL,                 /* next                 */
  51   IPPROTO_TCP,          /* protocol ID          */
  52   0,                    /* copy                 */
  53   NULL,                 /* data                 */
  54   "TCP"                 /* name                 */
  55 };
  56 
  57 
  58 static struct inet_protocol udp_protocol = {
  59   udp_rcv,              /* UDP handler          */
  60   NULL,                 /* Will be UDP fraglist handler */
  61   udp_err,              /* UDP error control    */
  62   &tcp_protocol,        /* next                 */
  63   IPPROTO_UDP,          /* protocol ID          */
  64   0,                    /* copy                 */
  65   NULL,                 /* data                 */
  66   "UDP"                 /* name                 */
  67 };
  68 
  69 
  70 static struct inet_protocol icmp_protocol = {
  71   icmp_rcv,             /* ICMP handler         */
  72   NULL,                 /* ICMP never fragments anyway */
  73   NULL,                 /* ICMP error control   */
  74   &udp_protocol,        /* next                 */
  75   IPPROTO_ICMP,         /* protocol ID          */
  76   0,                    /* copy                 */
  77   NULL,                 /* data                 */
  78   "ICMP"                /* name                 */
  79 };
  80 
  81 #ifndef CONFIG_IP_MULTICAST
  82 struct inet_protocol *inet_protocol_base = &icmp_protocol;
  83 #else
  84 static struct inet_protocol igmp_protocol = {
  85   igmp_rcv,             /* IGMP handler         */
  86   NULL,                 /* IGMP never fragments anyway */
  87   NULL,                 /* IGMP error control   */
  88   &icmp_protocol,       /* next                 */
  89   IPPROTO_IGMP,         /* protocol ID          */
  90   0,                    /* copy                 */
  91   NULL,                 /* data                 */
  92   "IGMP"                /* name                 */
  93 };
  94 
  95 struct inet_protocol *inet_protocol_base = &igmp_protocol;
  96 #endif
  97 
  98 struct inet_protocol *inet_protos[MAX_INET_PROTOS] = {
  99   NULL
 100 };
 101 
 102 
 103 struct inet_protocol *
 104 inet_get_protocol(unsigned char prot)
     /*  */
 105 {
 106   unsigned char hash;
 107   struct inet_protocol *p;
 108 
 109   hash = prot & (MAX_INET_PROTOS - 1);
 110   for (p = inet_protos[hash] ; p != NULL; p=p->next) {
 111         if (p->protocol == prot) return((struct inet_protocol *) p);
 112   }
 113   return(NULL);
 114 }
 115 
 116 
 117 void
 118 inet_add_protocol(struct inet_protocol *prot)
     /*  */
 119 {
 120   unsigned char hash;
 121   struct inet_protocol *p2;
 122 
 123   hash = prot->protocol & (MAX_INET_PROTOS - 1);
 124   prot ->next = inet_protos[hash];
 125   inet_protos[hash] = prot;
 126   prot->copy = 0;
 127 
 128   /* Set the copy bit if we need to. */
 129   p2 = (struct inet_protocol *) prot->next;
 130   while(p2 != NULL) {
 131         if (p2->protocol == prot->protocol) {
 132                 prot->copy = 1;
 133                 break;
 134         }
 135         p2 = (struct inet_protocol *) prot->next;
 136   }
 137 }
 138 
 139 
 140 int
 141 inet_del_protocol(struct inet_protocol *prot)
     /*  */
 142 {
 143   struct inet_protocol *p;
 144   struct inet_protocol *lp = NULL;
 145   unsigned char hash;
 146 
 147   hash = prot->protocol & (MAX_INET_PROTOS - 1);
 148   if (prot == inet_protos[hash]) {
 149         inet_protos[hash] = (struct inet_protocol *) inet_protos[hash]->next;
 150         return(0);
 151   }
 152 
 153   p = (struct inet_protocol *) inet_protos[hash];
 154   while(p != NULL) {
 155         /*
 156          * We have to worry if the protocol being deleted is
 157          * the last one on the list, then we may need to reset
 158          * someone's copied bit.
 159          */
 160         if (p->next != NULL && p->next == prot) {
 161                 /*
 162                  * if we are the last one with this protocol and
 163                  * there is a previous one, reset its copy bit.
 164                  */
 165              if (p->copy == 0 && lp != NULL) lp->copy = 0;
 166              p->next = prot->next;
 167              return(0);
 168         }
 169 
 170         if (p->next != NULL && p->next->protocol == prot->protocol) {
 171                 lp = p;
 172         }
 173 
 174         p = (struct inet_protocol *) p->next;
 175   }
 176   return(-1);
 177 }
/* */
root/net/inet/protocol.c

DEFINITIONS
