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 <linux/inet.h>
  33 #include <linux/netdevice.h>
  34 #include "ip.h"
  35 #include "protocol.h"
  36 #include "tcp.h"
  37 #include <linux/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   hash = prot & (MAX_INET_PROTOS - 1);
  92   for (p = inet_protos[hash] ; p != NULL; p=p->next) {
  93         if (p->protocol == prot) return((struct inet_protocol *) p);
  94   }
  95   return(NULL);
  96 }
  97 
  98 
  99 void
 100 inet_add_protocol(struct inet_protocol *prot)
     /*  */
 101 {
 102   unsigned char hash;
 103   struct inet_protocol *p2;
 104 
 105   hash = prot->protocol & (MAX_INET_PROTOS - 1);
 106   prot ->next = inet_protos[hash];
 107   inet_protos[hash] = prot;
 108   prot->copy = 0;
 109 
 110   /* Set the copy bit if we need to. */
 111   p2 = (struct inet_protocol *) prot->next;
 112   while(p2 != NULL) {
 113         if (p2->protocol == prot->protocol) {
 114                 prot->copy = 1;
 115                 break;
 116         }
 117         p2 = (struct inet_protocol *) prot->next;
 118   }
 119 }
 120 
 121 
 122 int
 123 inet_del_protocol(struct inet_protocol *prot)
     /*  */
 124 {
 125   struct inet_protocol *p;
 126   struct inet_protocol *lp = NULL;
 127   unsigned char hash;
 128 
 129   hash = prot->protocol & (MAX_INET_PROTOS - 1);
 130   if (prot == inet_protos[hash]) {
 131         inet_protos[hash] = (struct inet_protocol *) inet_protos[hash]->next;
 132         return(0);
 133   }
 134 
 135   p = (struct inet_protocol *) inet_protos[hash];
 136   while(p != NULL) {
 137         /*
 138          * We have to worry if the protocol being deleted is
 139          * the last one on the list, then we may need to reset
 140          * someone's copied bit.
 141          */
 142         if (p->next != NULL && p->next == prot) {
 143                 /*
 144                  * if we are the last one with this protocol and
 145                  * there is a previous one, reset its copy bit.
 146                  */
 147              if (p->copy == 0 && lp != NULL) lp->copy = 0;
 148              p->next = prot->next;
 149              return(0);
 150         }
 151 
 152         if (p->next != NULL && p->next->protocol == prot->protocol) {
 153                 lp = p;
 154         }
 155 
 156         p = (struct inet_protocol *) p->next;
 157   }
 158   return(-1);
 159 }
/* */
root/net/inet/protocol.c

DEFINITIONS
