1 /* ip_output.c 6.1 83/07/29 */ 2 3 #include "../h/param.h" 4 #include "../h/mbuf.h" 5 #include "../h/errno.h" 6 #include "../h/socket.h" 7 #include "../h/socketvar.h" 8 9 #include "../net/if.h" 10 #include "../net/route.h" 11 12 #include "../netinet/in.h" 13 #include "../netinet/in_systm.h" 14 #include "../netinet/ip.h" 15 #include "../netinet/ip_var.h" 16 17 #ifdef vax 18 #include "../vax/mtpr.h" 19 #endif 20 21 ip_output(m, opt, ro, flags) 22 struct mbuf *m; 23 struct mbuf *opt; 24 struct route *ro; 25 int flags; 26 { 27 register struct ip *ip = mtod(m, struct ip *); 28 register struct ifnet *ifp; 29 int len, hlen = sizeof (struct ip), off, error = 0; 30 struct route iproute; 31 struct sockaddr *dst; 32 33 if (opt) /* XXX */ 34 (void) m_free(opt); /* XXX */ 35 /* 36 * Fill in IP header. 37 */ 38 ip->ip_hl = hlen >> 2; 39 if ((flags & IP_FORWARDING) == 0) { 40 ip->ip_v = IPVERSION; 41 ip->ip_off &= IP_DF; 42 ip->ip_id = htons(ip_id++); 43 } 44 45 /* 46 * Route packet. 47 */ 48 if (ro == 0) { 49 ro = &iproute; 50 bzero((caddr_t)ro, sizeof (*ro)); 51 } 52 dst = &ro->ro_dst; 53 if (ro->ro_rt == 0) { 54 ro->ro_dst.sa_family = AF_INET; 55 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = ip->ip_dst; 56 /* 57 * If routing to interface only, 58 * short circuit routing lookup. 59 */ 60 if (flags & IP_ROUTETOIF) { 61 ifp = if_ifonnetof(in_netof(ip->ip_dst)); 62 if (ifp == 0) { 63 error = ENETUNREACH; 64 goto bad; 65 } 66 goto gotif; 67 } 68 rtalloc(ro); 69 } 70 if (ro->ro_rt == 0 || (ifp = ro->ro_rt->rt_ifp) == 0) { 71 error = ENETUNREACH; 72 goto bad; 73 } 74 ro->ro_rt->rt_use++; 75 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 76 dst = &ro->ro_rt->rt_gateway; 77 gotif: 78 #ifndef notdef 79 /* 80 * If source address not specified yet, use address 81 * of outgoing interface. 82 */ 83 if (in_lnaof(ip->ip_src) == INADDR_ANY) 84 ip->ip_src.s_addr = 85 ((struct sockaddr_in *)&ifp->if_addr)->sin_addr.s_addr; 86 #endif 87 88 /* 89 * Look for broadcast address and 90 * and verify user is allowed to send 91 * such a packet. 92 */ 93 if (in_lnaof(((struct sockaddr_in *)dst)->sin_addr) == INADDR_ANY) { 94 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 95 error = EADDRNOTAVAIL; 96 goto bad; 97 } 98 if ((flags & IP_ALLOWBROADCAST) == 0) { 99 error = EACCES; 100 goto bad; 101 } 102 /* don't allow broadcast messages to be fragmented */ 103 if (ip->ip_len > ifp->if_mtu) { 104 error = EMSGSIZE; 105 goto bad; 106 } 107 } 108 109 /* 110 * If small enough for interface, can just send directly. 111 */ 112 if (ip->ip_len <= ifp->if_mtu) { 113 ip->ip_len = htons((u_short)ip->ip_len); 114 ip->ip_off = htons((u_short)ip->ip_off); 115 ip->ip_sum = 0; 116 ip->ip_sum = in_cksum(m, hlen); 117 error = (*ifp->if_output)(ifp, m, dst); 118 goto done; 119 } 120 121 /* 122 * Too large for interface; fragment if possible. 123 * Must be able to put at least 8 bytes per fragment. 124 */ 125 if (ip->ip_off & IP_DF) { 126 error = EMSGSIZE; 127 goto bad; 128 } 129 len = (ifp->if_mtu - hlen) &~ 7; 130 if (len < 8) { 131 error = EMSGSIZE; 132 goto bad; 133 } 134 135 /* 136 * Discard IP header from logical mbuf for m_copy's sake. 137 * Loop through length of segment, make a copy of each 138 * part and output. 139 */ 140 m->m_len -= sizeof (struct ip); 141 m->m_off += sizeof (struct ip); 142 for (off = 0; off < ip->ip_len-hlen; off += len) { 143 struct mbuf *mh = m_get(M_DONTWAIT, MT_HEADER); 144 struct ip *mhip; 145 146 if (mh == 0) { 147 error = ENOBUFS; 148 goto bad; 149 } 150 mh->m_off = MMAXOFF - hlen; 151 mhip = mtod(mh, struct ip *); 152 *mhip = *ip; 153 if (hlen > sizeof (struct ip)) { 154 int olen = ip_optcopy(ip, mhip, off); 155 mh->m_len = sizeof (struct ip) + olen; 156 } else 157 mh->m_len = sizeof (struct ip); 158 mhip->ip_off = off >> 3; 159 if (off + len >= ip->ip_len-hlen) 160 len = mhip->ip_len = ip->ip_len - hlen - off; 161 else { 162 mhip->ip_len = len; 163 mhip->ip_off |= IP_MF; 164 } 165 mhip->ip_len += sizeof (struct ip); 166 mhip->ip_len = htons((u_short)mhip->ip_len); 167 mh->m_next = m_copy(m, off, len); 168 if (mh->m_next == 0) { 169 (void) m_free(mh); 170 error = ENOBUFS; /* ??? */ 171 goto bad; 172 } 173 mhip->ip_off = htons((u_short)mhip->ip_off); 174 mhip->ip_sum = 0; 175 mhip->ip_sum = in_cksum(mh, hlen); 176 if (error = (*ifp->if_output)(ifp, mh, dst)) 177 break; 178 } 179 m_freem(m); 180 goto done; 181 182 bad: 183 m_freem(m); 184 done: 185 if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt) 186 RTFREE(ro->ro_rt); 187 return (error); 188 } 189 190 /* 191 * Copy options from ip to jp. 192 * If off is 0 all options are copied 193 * otherwise copy selectively. 194 */ 195 ip_optcopy(ip, jp, off) 196 struct ip *ip, *jp; 197 int off; 198 { 199 register u_char *cp, *dp; 200 int opt, optlen, cnt; 201 202 cp = (u_char *)(ip + 1); 203 dp = (u_char *)(jp + 1); 204 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 205 for (; cnt > 0; cnt -= optlen, cp += optlen) { 206 opt = cp[0]; 207 if (opt == IPOPT_EOL) 208 break; 209 if (opt == IPOPT_NOP) 210 optlen = 1; 211 else 212 optlen = cp[1]; 213 if (optlen > cnt) /* XXX */ 214 optlen = cnt; /* XXX */ 215 if (off == 0 || IPOPT_COPIED(opt)) { 216 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 217 dp += optlen; 218 } 219 } 220 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 221 *dp++ = IPOPT_EOL; 222 return (optlen); 223 } 224