usr.sbin/mrouted/icmp.c

   1 /*
   2  * The mrouted program is covered by the license in the accompanying file
   3  * named "LICENSE".  Use of the mrouted program represents acceptance of
   4  * the terms and conditions listed in that file.
   5  *
   6  * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
   7  * Leland Stanford Junior University.
   8  *
   9  *
  10  * icmp.c,v 3.8.4.2 1998/01/06 01:57:42 fenner Exp
  11  */
  12
  13 #include "defs.h"
  14
  15 #ifndef lint
  16 static char rcsid[] = "@(#) $Id: \
  17 icmp.c,v 3.8.4.2 1998/01/06 01:57:42 fenner Exp $";
  18 #endif
  19
  20 static int      icmp_socket;
  21
  22 static void     icmp_handler __P((int, fd_set *));
  23 static char *   icmp_name __P((struct icmp *));
  24
  25 void
  26 init_icmp()
  27 {
  28     if ((icmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0)
  29         log(LOG_ERR, errno, "ICMP socket");
  30
  31     register_input_handler(icmp_socket, icmp_handler);
  32
  33     IF_DEBUG(DEBUG_ICMP)
  34     log(LOG_DEBUG, 0, "registering icmp socket fd %d\n", icmp_socket);
  35 }
  36
  37 static void
  38 icmp_handler(fd, rfds)
  39     int fd;
  40     fd_set *rfds;
  41 {
  42     u_char icmp_buf[RECV_BUF_SIZE];
  43     struct sockaddr_in from;
  44     int fromlen, recvlen, iphdrlen, ipdatalen;
  45     struct icmp *icmp;
  46     struct ip *ip;
  47     vifi_t i;
  48     struct uvif *v;
  49     u_int32 src;
  50
  51     fromlen = sizeof(from);
  52     recvlen = recvfrom(icmp_socket, icmp_buf, RECV_BUF_SIZE, 0,
  53                             (struct sockaddr *)&from, &fromlen);
  54     if (recvlen < 0) {
  55         if (errno != EINTR)
  56             log(LOG_WARNING, errno, "icmp_socket recvfrom");
  57         return;
  58     }
  59     ip = (struct ip *)icmp_buf;
  60     iphdrlen = ip->ip_hl << 2;
  61 #ifdef RAW_INPUT_IS_RAW
  62     ipdatalen = ntohs(ip->ip_len) - iphdrlen;
  63 #else
  64     ipdatalen = ip->ip_len;
  65 #endif
  66     if (iphdrlen + ipdatalen != recvlen) {
  67         IF_DEBUG(DEBUG_ICMP)
  68         log(LOG_DEBUG, 0, "hdr %d data %d != rcv %d", iphdrlen, ipdatalen, recvlen);
  69         /* Malformed ICMP, just return. */
  70         return;
  71     }
  72     if (ipdatalen < ICMP_MINLEN + sizeof(struct ip)) {
  73         /* Not enough data for us to be interested in it. */
  74         return;
  75     }
  76     src = ip->ip_src.s_addr;
  77     icmp = (struct icmp *)(icmp_buf + iphdrlen);
  78     IF_DEBUG(DEBUG_ICMP)
  79     log(LOG_DEBUG, 0, "got ICMP type %d from %s",
  80         icmp->icmp_type, inet_fmt(src, s1));
  81     /*
  82      * Eventually:
  83      * have registry of ICMP listeners, by type, code and ICMP_ID
  84      * (and maybe fields of the original packet too -- maybe need a
  85      * generalized packet filter!) to allow ping and traceroute
  86      * from the monitoring tool.
  87      */
  88     switch (icmp->icmp_type) {
  89         case ICMP_UNREACH:
  90         case ICMP_TIMXCEED:
  91             /* Look at returned packet to see if it's us sending on a tunnel */
  92             ip = &icmp->icmp_ip;
  93             if (ip->ip_p != IPPROTO_IGMP && ip->ip_p != IPPROTO_IPIP)
  94                 return;
  95             for (v = uvifs, i = 0; i < numvifs; v++, i++) {
  96                 if (ip->ip_src.s_addr == v->uv_lcl_addr &&
  97                     ip->ip_dst.s_addr == v->uv_dst_addr) {
  98                     char *p;
  99                     int n;
 100                     /*
 101                      * I sent this packet on this vif.
 102                      */
 103                     n = ++v->uv_icmp_warn;
 104                     while (n && !(n & 1))
 105                         n >>= 1;
 106                     if (n == 1 && ((p = icmp_name(icmp)) != NULL))
 107                         log(LOG_WARNING, 0, "Received ICMP %s from %s %s %s on vif %d",
 108                             p, inet_fmt(src, s1), "for traffic sent to",
 109                             inet_fmt(ip->ip_dst.s_addr, s2),
 110                             i);
 111
 112                     break;
 113                 }
 114             }
 115             break;
 116     }
 117 }
 118
 119 /*
 120  * Return NULL for ICMP informational messages.
 121  * Return string describing the error for ICMP errors.
 122  */
 123 static char *
 124 icmp_name(icmp)
 125     struct icmp *icmp;
 126 {
 127     static char retval[30];
 128
 129     switch (icmp->icmp_type) {
 130         case ICMP_UNREACH:
 131             switch (icmp->icmp_code) {
 132                 case ICMP_UNREACH_NET:
 133                     return "network unreachable";
 134                 case ICMP_UNREACH_HOST:
 135                     return "host unreachable";
 136                 case ICMP_UNREACH_PROTOCOL:
 137                     return "protocol unreachable";
 138                 case ICMP_UNREACH_PORT:
 139                     return "port unreachable";
 140                 case ICMP_UNREACH_NEEDFRAG:
 141                     return "needs fragmentation";
 142                 case ICMP_UNREACH_SRCFAIL:
 143                     return "source route failed";
 144 #ifndef ICMP_UNREACH_NET_UNKNOWN
 145 #define ICMP_UNREACH_NET_UNKNOWN        6
 146 #endif
 147                 case ICMP_UNREACH_NET_UNKNOWN:
 148                     return "network unknown";
 149 #ifndef ICMP_UNREACH_HOST_UNKNOWN
 150 #define ICMP_UNREACH_HOST_UNKNOWN       7
 151 #endif
 152                 case ICMP_UNREACH_HOST_UNKNOWN:
 153                     return "host unknown";
 154 #ifndef ICMP_UNREACH_ISOLATED
 155 #define ICMP_UNREACH_ISOLATED           8
 156 #endif
 157                 case ICMP_UNREACH_ISOLATED:
 158                     return "source host isolated";
 159 #ifndef ICMP_UNREACH_NET_PROHIB
 160 #define ICMP_UNREACH_NET_PROHIB         9
 161 #endif
 162                 case ICMP_UNREACH_NET_PROHIB:
 163                     return "network access prohibited";
 164 #ifndef ICMP_UNREACH_HOST_PROHIB
 165 #define ICMP_UNREACH_HOST_PROHIB        10
 166 #endif
 167                 case ICMP_UNREACH_HOST_PROHIB:
 168                     return "host access prohibited";
 169 #ifndef ICMP_UNREACH_TOSNET
 170 #define ICMP_UNREACH_TOSNET             11
 171 #endif
 172                 case ICMP_UNREACH_TOSNET:
 173                     return "bad TOS for net";
 174 #ifndef ICMP_UNREACH_TOSHOST
 175 #define ICMP_UNREACH_TOSHOST            12
 176 #endif
 177                 case ICMP_UNREACH_TOSHOST:
 178                     return "bad TOS for host";
 179 #ifndef ICMP_UNREACH_FILTER_PROHIB
 180 #define ICMP_UNREACH_FILTER_PROHIB      13
 181 #endif
 182                 case ICMP_UNREACH_FILTER_PROHIB:
 183                     return "prohibited by filter";
 184 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
 185 #define ICMP_UNREACH_HOST_PRECEDENCE    14
 186 #endif
 187                 case ICMP_UNREACH_HOST_PRECEDENCE:
 188                     return "host precedence violation";
 189 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
 190 #define ICMP_UNREACH_PRECEDENCE_CUTOFF  15
 191 #endif
 192                 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
 193                     return "precedence cutoff";
 194                 default:
 195                     sprintf(retval, "unreachable code %d", icmp->icmp_code);
 196                     return retval;
 197             }
 198         case ICMP_SOURCEQUENCH:
 199             return "source quench";
 200         case ICMP_REDIRECT:
 201             return NULL;        /* XXX */
 202         case ICMP_TIMXCEED:
 203             switch (icmp->icmp_code) {
 204                 case ICMP_TIMXCEED_INTRANS:
 205                     return "time exceeded in transit";
 206                 case ICMP_TIMXCEED_REASS:
 207                     return "time exceeded in reassembly";
 208                 default:
 209                     sprintf(retval, "time exceeded code %d", icmp->icmp_code);
 210                     return retval;
 211             }
 212         case ICMP_PARAMPROB:
 213             switch (icmp->icmp_code) {
 214 #ifndef ICMP_PARAMPROB_OPTABSENT
 215 #define ICMP_PARAMPROB_OPTABSENT        1
 216 #endif
 217                 case ICMP_PARAMPROB_OPTABSENT:
 218                     return "required option absent";
 219                 default:
 220                     sprintf(retval, "parameter problem code %d", icmp->icmp_code);
 221                     return retval;
 222             }
 223     }
 224     return NULL;
 225 }