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/socket.h>
  31 #include <linux/in.h>
  32 #include "inet.h"
  33 #include "dev.h"
  34 #include "ip.h"
  35 #include "protocol.h"
  36 #include "tcp.h"
  37 #include "skbuff.h"
  38 #include "sock.h"
  39 #include "icmp.h"
  40 #include "udp.h"
  41 
  42 
  43 static struct inet_protocol tcp_protocol = {
  44   tcp_rcv,              /* TCP handler          */
  45   NULL,                 /* No fragment handler (and won't be for a long time) */
  46   tcp_err,              /* TCP error control    */
  47   NULL,                 /* next                 */
  48   IPPROTO_TCP,          /* protocol ID          */
  49   0,                    /* copy                 */
  50   NULL,                 /* data                 */
  51   "TCP"                 /* name                 */
  52 };
  53 
  54 
  55 static struct inet_protocol udp_protocol = {
  56   udp_rcv,              /* UDP handler          */
  57   NULL,                 /* Will be UDP fraglist handler */
  58   udp_err,              /* UDP error control    */
  59   &tcp_protocol,        /* next                 */
  60   IPPROTO_UDP,          /* protocol ID          */
  61   0,                    /* copy                 */
  62   NULL,                 /* data                 */
  63   "UDP"                 /* name                 */
  64 };
  65 
  66 
  67 static struct inet_protocol icmp_protocol = {
  68   icmp_rcv,             /* ICMP handler         */
  69   NULL,                 /* ICMP never fragments anyway */
  70   NULL,                 /* ICMP error control   */
  71   &udp_protocol,        /* next                 */
  72   IPPROTO_ICMP,         /* protocol ID          */
  73   0,                    /* copy                 */
  74   NULL,                 /* data                 */
  75   "ICMP"                /* name                 */
  76 };
  77 
  78 
  79 struct inet_protocol *inet_protocol_base = &icmp_protocol;
  80 struct inet_protocol *inet_protos[MAX_INET_PROTOS] = {
  81   NULL
  82 };
  83 
  84 
  85 struct inet_protocol *
  86 inet_get_protocol(unsigned char prot)
     /*  */
  87 {
  88   unsigned char hash;
  89   struct inet_protocol *p;
  90 
  91   DPRINTF((DBG_PROTO, "get_protocol (%d)\n ", prot));
  92   hash = prot & (MAX_INET_PROTOS - 1);
  93   for (p = inet_protos[hash] ; p != NULL; p=p->next) {
  94         DPRINTF((DBG_PROTO, "trying protocol %d\n", p->protocol));
  95         if (p->protocol == prot) return((struct inet_protocol *) p);
  96   }
  97   return(NULL);
  98 }
  99 
 100 
 101 void
 102 inet_add_protocol(struct inet_protocol *prot)
     /*  */
 103 {
 104   unsigned char hash;
 105   struct inet_protocol *p2;
 106 
 107   hash = prot->protocol & (MAX_INET_PROTOS - 1);
 108   prot ->next = inet_protos[hash];
 109   inet_protos[hash] = prot;
 110   prot->copy = 0;
 111 
 112   /* Set the copy bit if we need to. */
 113   p2 = (struct inet_protocol *) prot->next;
 114   while(p2 != NULL) {
 115         if (p2->protocol == prot->protocol) {
 116                 prot->copy = 1;
 117                 break;
 118         }
 119         p2 = (struct inet_protocol *) prot->next;
 120   }
 121 }
 122 
 123 
 124 int
 125 inet_del_protocol(struct inet_protocol *prot)
     /*  */
 126 {
 127   struct inet_protocol *p;
 128   struct inet_protocol *lp = NULL;
 129   unsigned char hash;
 130 
 131   hash = prot->protocol & (MAX_INET_PROTOS - 1);
 132   if (prot == inet_protos[hash]) {
 133         inet_protos[hash] = (struct inet_protocol *) inet_protos[hash]->next;
 134         return(0);
 135   }
 136 
 137   p = (struct inet_protocol *) inet_protos[hash];
 138   while(p != NULL) {
 139         /*
 140          * We have to worry if the protocol being deleted is
 141          * the last one on the list, then we may need to reset
 142          * someones copied bit.
 143          */
 144         if (p->next != NULL && p->next == prot) {
 145                 /*
 146                  * if we are the last one with this protocol and
 147                  * there is a previous one, reset its copy bit.
 148                  */
 149              if (p->copy == 0 && lp != NULL) lp->copy = 0;
 150              p->next = prot->next;
 151              return(0);
 152         }
 153 
 154         if (p->next != NULL && p->next->protocol == prot->protocol) {
 155                 lp = p;
 156         }
 157 
 158         p = (struct inet_protocol *) p->next;
 159   }
 160   return(-1);
 161 }
/* */
root/net/inet/protocol.c

DEFINITIONS
