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  * @(#) $Id icmp.c,v 3.8.4.2 1998/01/06 01:57:42 fenner Exp $
  11  * $DragonFly: src/usr.sbin/mrouted/icmp.c,v 1.4 2004/03/15 18:10:28 dillon Exp $
  12  */
  13
  14 #include "defs.h"
  15
  16 static int      icmp_socket;
  17
  18 static void     icmp_handler(int, fd_set *);
  19 static char *   icmp_name(struct icmp *);
  20
  21 void
  22 init_icmp(void)
  23 {
  24     if ((icmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0)
  25         dolog(LOG_ERR, errno, "ICMP socket");
  26
  27     register_input_handler(icmp_socket, icmp_handler);
  28
  29     IF_DEBUG(DEBUG_ICMP)
  30     dolog(LOG_DEBUG, 0, "registering icmp socket fd %d\n", icmp_socket);
  31 }
  32
  33 static void
  34 icmp_handler(int fd, fd_set *rfds)
  35 {
  36     u_char icmp_buf[RECV_BUF_SIZE];
  37     struct sockaddr_in from;
  38     int fromlen, recvlen, iphdrlen, ipdatalen;
  39     struct icmp *icmp;
  40     struct ip *ip;
  41     vifi_t i;
  42     struct uvif *v;
  43     u_int32 src;
  44
  45     fromlen = sizeof(from);
  46     recvlen = recvfrom(icmp_socket, icmp_buf, RECV_BUF_SIZE, 0,
  47                             (struct sockaddr *)&from, &fromlen);
  48     if (recvlen < 0) {
  49         if (errno != EINTR)
  50             dolog(LOG_WARNING, errno, "icmp_socket recvfrom");
  51         return;
  52     }
  53     ip = (struct ip *)icmp_buf;
  54     iphdrlen = ip->ip_hl << 2;
  55 #ifdef RAW_INPUT_IS_RAW
  56     ipdatalen = ntohs(ip->ip_len) - iphdrlen;
  57 #else
  58     ipdatalen = ip->ip_len;
  59 #endif
  60     if (iphdrlen + ipdatalen != recvlen) {
  61         IF_DEBUG(DEBUG_ICMP)
  62         dolog(LOG_DEBUG, 0, "hdr %d data %d != rcv %d", iphdrlen, ipdatalen, recvlen);
  63         /* Malformed ICMP, just return. */
  64         return;
  65     }
  66     if (ipdatalen < ICMP_MINLEN + sizeof(struct ip)) {
  67         /* Not enough data for us to be interested in it. */
  68         return;
  69     }
  70     src = ip->ip_src.s_addr;
  71     icmp = (struct icmp *)(icmp_buf + iphdrlen);
  72     IF_DEBUG(DEBUG_ICMP)
  73     dolog(LOG_DEBUG, 0, "got ICMP type %d from %s",
  74         icmp->icmp_type, inet_fmt(src, s1));
  75     /*
  76      * Eventually:
  77      * have registry of ICMP listeners, by type, code and ICMP_ID
  78      * (and maybe fields of the original packet too -- maybe need a
  79      * generalized packet filter!) to allow ping and traceroute
  80      * from the monitoring tool.
  81      */
  82     switch (icmp->icmp_type) {
  83         case ICMP_UNREACH:
  84         case ICMP_TIMXCEED:
  85             /* Look at returned packet to see if it's us sending on a tunnel */
  86             ip = &icmp->icmp_ip;
  87             if (ip->ip_p != IPPROTO_IGMP && ip->ip_p != IPPROTO_IPIP)
  88                 return;
  89             for (v = uvifs, i = 0; i < numvifs; v++, i++) {
  90                 if (ip->ip_src.s_addr == v->uv_lcl_addr &&
  91                     ip->ip_dst.s_addr == v->uv_dst_addr) {
  92                     char *p;
  93                     int n;
  94                     /*
  95                      * I sent this packet on this vif.
  96                      */
  97                     n = ++v->uv_icmp_warn;
  98                     while (n && !(n & 1))
  99                         n >>= 1;
 100                     if (n == 1 && ((p = icmp_name(icmp)) != NULL))
 101                         dolog(LOG_WARNING, 0, "Received ICMP %s from %s %s %s on vif %d",
 102                             p, inet_fmt(src, s1), "for traffic sent to",
 103                             inet_fmt(ip->ip_dst.s_addr, s2),
 104                             i);
 105
 106                     break;
 107                 }
 108             }
 109             break;
 110     }
 111 }
 112
 113 /*
 114  * Return NULL for ICMP informational messages.
 115  * Return string describing the error for ICMP errors.
 116  */
 117 static char *
 118 icmp_name(struct icmp *icmp)
 119 {
 120     static char retval[30];
 121
 122     switch (icmp->icmp_type) {
 123         case ICMP_UNREACH:
 124             switch (icmp->icmp_code) {
 125                 case ICMP_UNREACH_NET:
 126                     return "network unreachable";
 127                 case ICMP_UNREACH_HOST:
 128                     return "host unreachable";
 129                 case ICMP_UNREACH_PROTOCOL:
 130                     return "protocol unreachable";
 131                 case ICMP_UNREACH_PORT:
 132                     return "port unreachable";
 133                 case ICMP_UNREACH_NEEDFRAG:
 134                     return "needs fragmentation";
 135                 case ICMP_UNREACH_SRCFAIL:
 136                     return "source route failed";
 137 #ifndef ICMP_UNREACH_NET_UNKNOWN
 138 #define ICMP_UNREACH_NET_UNKNOWN        6
 139 #endif
 140                 case ICMP_UNREACH_NET_UNKNOWN:
 141                     return "network unknown";
 142 #ifndef ICMP_UNREACH_HOST_UNKNOWN
 143 #define ICMP_UNREACH_HOST_UNKNOWN       7
 144 #endif
 145                 case ICMP_UNREACH_HOST_UNKNOWN:
 146                     return "host unknown";
 147 #ifndef ICMP_UNREACH_ISOLATED
 148 #define ICMP_UNREACH_ISOLATED           8
 149 #endif
 150                 case ICMP_UNREACH_ISOLATED:
 151                     return "source host isolated";
 152 #ifndef ICMP_UNREACH_NET_PROHIB
 153 #define ICMP_UNREACH_NET_PROHIB         9
 154 #endif
 155                 case ICMP_UNREACH_NET_PROHIB:
 156                     return "network access prohibited";
 157 #ifndef ICMP_UNREACH_HOST_PROHIB
 158 #define ICMP_UNREACH_HOST_PROHIB        10
 159 #endif
 160                 case ICMP_UNREACH_HOST_PROHIB:
 161                     return "host access prohibited";
 162 #ifndef ICMP_UNREACH_TOSNET
 163 #define ICMP_UNREACH_TOSNET             11
 164 #endif
 165                 case ICMP_UNREACH_TOSNET:
 166                     return "bad TOS for net";
 167 #ifndef ICMP_UNREACH_TOSHOST
 168 #define ICMP_UNREACH_TOSHOST            12
 169 #endif
 170                 case ICMP_UNREACH_TOSHOST:
 171                     return "bad TOS for host";
 172 #ifndef ICMP_UNREACH_FILTER_PROHIB
 173 #define ICMP_UNREACH_FILTER_PROHIB      13
 174 #endif
 175                 case ICMP_UNREACH_FILTER_PROHIB:
 176                     return "prohibited by filter";
 177 #ifndef ICMP_UNREACH_HOST_PRECEDENCE
 178 #define ICMP_UNREACH_HOST_PRECEDENCE    14
 179 #endif
 180                 case ICMP_UNREACH_HOST_PRECEDENCE:
 181                     return "host precedence violation";
 182 #ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
 183 #define ICMP_UNREACH_PRECEDENCE_CUTOFF  15
 184 #endif
 185                 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
 186                     return "precedence cutoff";
 187                 default:
 188                     sprintf(retval, "unreachable code %d", icmp->icmp_code);
 189                     return retval;
 190             }
 191         case ICMP_SOURCEQUENCH:
 192             return "source quench";
 193         case ICMP_REDIRECT:
 194             return NULL;        /* XXX */
 195         case ICMP_TIMXCEED:
 196             switch (icmp->icmp_code) {
 197                 case ICMP_TIMXCEED_INTRANS:
 198                     return "time exceeded in transit";
 199                 case ICMP_TIMXCEED_REASS:
 200                     return "time exceeded in reassembly";
 201                 default:
 202                     sprintf(retval, "time exceeded code %d", icmp->icmp_code);
 203                     return retval;
 204             }
 205         case ICMP_PARAMPROB:
 206             switch (icmp->icmp_code) {
 207 #ifndef ICMP_PARAMPROB_OPTABSENT
 208 #define ICMP_PARAMPROB_OPTABSENT        1
 209 #endif
 210                 case ICMP_PARAMPROB_OPTABSENT:
 211                     return "required option absent";
 212                 default:
 213                     sprintf(retval, "parameter problem code %d", icmp->icmp_code);
 214                     return retval;
 215             }
 216     }
 217     return NULL;
 218 }