usr.sbin/mrouted/ipip.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 ipip.c,v 3.8.4.6 1998/01/06 01:57:45 fenner Exp $
  11  * $DragonFly: src/usr.sbin/mrouted/ipip.c,v 1.3 2004/03/15 18:10:28 dillon Exp $
  12  */
  13
  14 #include "defs.h"
  15
  16 /*
  17  * Exported variables.
  18  */
  19 #ifdef notyet
  20 int             raw_socket;                 /* socket for raw network I/O  */
  21 #endif
  22 /*
  23  *XXX For now, we just use the IGMP socket to send packets.
  24  * This is legal in BSD, because the protocol # is not checked
  25  * on raw sockets.  The k_* interfaces need to gain a socket
  26  * argument so that we can call them on the raw_socket also.
  27  */
  28 #define raw_socket      igmp_socket
  29
  30 /*
  31  * Private variables.
  32  */
  33 static int rawid = 0;
  34
  35 /*
  36  * Open and initialize the raw socket.
  37  */
  38 void
  39 init_ipip(void)
  40 {
  41 #ifdef notyet
  42     if ((raw_socket = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0)
  43         log(LOG_ERR, errno, "Raw IP socket");
  44 #endif
  45 }
  46
  47 /*
  48  * Allocate and fill in static IP header for encapsulating on a tunnel.
  49  */
  50 void
  51 init_ipip_on_vif(struct uvif *v)
  52 {
  53     struct ip *ip;
  54
  55     ip = v->uv_encap_hdr = (struct ip *)malloc(sizeof(struct ip));
  56     if (ip == NULL)
  57         log(LOG_ERR, 0, "out of memory");
  58     bzero(ip, sizeof(struct ip));
  59     /*
  60      * Fields zeroed that aren't filled in later:
  61      * - IP ID (let the kernel fill it in)
  62      * - Offset (we don't send fragments)
  63      * - Checksum (let the kernel fill it in)
  64      */
  65     ip->ip_v   = IPVERSION;
  66     ip->ip_hl  = sizeof(struct ip) >> 2;
  67     ip->ip_tos = 0xc0;          /* Internet Control */
  68     ip->ip_ttl = MAXTTL;        /* applies to unicasts only */
  69     ip->ip_p   = IPPROTO_IPIP;
  70     ip->ip_src.s_addr = v->uv_lcl_addr;
  71     ip->ip_dst.s_addr = v->uv_rmt_addr;
  72 }
  73
  74 /*
  75  * Call build_igmp() to build an IGMP message in the output packet buffer.
  76  * Then fill in the fields of the IP packet that build_igmp() left for the
  77  * kernel to fill in, and encapsulate the original packet with the
  78  * pre-created ip header for this vif.
  79  */
  80 void
  81 send_ipip(u_int32 src, u_int32 dst, int type, int code, u_int32 group,
  82           int datalen, struct uvif *v)
  83 {
  84     struct msghdr msg;
  85     struct iovec iov[2];
  86     struct sockaddr_in sdst;
  87     struct ip *ip;
  88
  89     build_igmp(src, dst, type, code, group, datalen);
  90     ip = (struct ip *)send_buf;
  91 #ifndef RAW_OUTPUT_IS_RAW
  92     ip->ip_len = htons(ip->ip_len);
  93 #endif
  94     ip->ip_id = htons(rawid++);
  95     ip->ip_sum = 0;
  96     ip->ip_sum = inet_cksum((u_short *)ip, ip->ip_hl << 2);
  97
  98     ip = v->uv_encap_hdr;
  99     ip->ip_len = 2 * MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen;
 100 #ifdef RAW_OUTPUT_IS_RAW
 101     ip->ip_len = htons(ip->ip_len);
 102 #endif
 103
 104     bzero(&sdst, sizeof(sdst));
 105     sdst.sin_family = AF_INET;
 106 #ifdef HAVE_SA_LEN
 107     sdst.sin_len = sizeof(sdst);
 108 #endif
 109     sdst.sin_addr = ip->ip_dst;
 110
 111     iov[0].iov_base = (caddr_t)v->uv_encap_hdr;
 112     iov[0].iov_len = sizeof(struct ip);
 113     iov[1].iov_base = (caddr_t)send_buf;
 114     iov[1].iov_len = MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen;
 115
 116     bzero(&msg, sizeof(msg));
 117     msg.msg_name = (caddr_t)&sdst;
 118     msg.msg_namelen = sizeof(sdst);
 119     msg.msg_iov = iov;
 120     msg.msg_iovlen = 2;
 121     if (sendmsg(raw_socket, &msg, 0) < 0) {
 122         if (errno == ENETDOWN)
 123             check_vif_state();
 124         else
 125             log(LOG_WARNING, errno,
 126                 "sendmsg to %s on %s",
 127                 inet_fmt(sdst.sin_addr.s_addr, s1), inet_fmt(src, s2));
 128     }
 129
 130     IF_DEBUG(DEBUG_PKT|igmp_debug_kind(type, code))
 131     log(LOG_DEBUG, 0, "SENT %s from %-15s to %s encaped to %s",
 132         igmp_packet_kind(type, code), src == INADDR_ANY ? "INADDR_ANY" :
 133                                  inet_fmt(src, s1), inet_fmt(dst, s2),
 134                                  inet_fmt(sdst.sin_addr.s_addr, s3));
 135 }