1 /* ip_output.c 1.31 82/03/31 */ 2 3 #include "../h/param.h" 4 #include "../h/mbuf.h" 5 #include "../h/mtpr.h" 6 #include "../h/socket.h" 7 #include "../h/socketvar.h" 8 #include "../net/in.h" 9 #include "../net/in_systm.h" 10 #include "../net/if.h" 11 #include "../net/ip.h" 12 #include "../net/ip_var.h" 13 #include "../net/route.h" 14 15 ip_output(m, opt, ro, allowbroadcast) 16 struct mbuf *m; 17 struct mbuf *opt; 18 struct route *ro; 19 int allowbroadcast; 20 { 21 register struct ip *ip = mtod(m, struct ip *); 22 register struct ifnet *ifp; 23 int len, hlen = sizeof (struct ip), off; 24 struct route iproute; 25 struct sockaddr *dst; 26 27 COUNT(IP_OUTPUT); 28 if (opt) /* XXX */ 29 (void) m_free(opt); /* XXX */ 30 /* 31 * Fill in IP header. 32 */ 33 ip->ip_v = IPVERSION; 34 ip->ip_hl = hlen >> 2; 35 ip->ip_off &= IP_DF; 36 ip->ip_id = htons(ip_id++); 37 38 /* 39 * Find interface for this packet in the routing 40 * table. Note each interface has placed itself 41 * in there at boot time, so calls to rtalloc 42 * degenerate to if_ifonnetof(ip->ip_dst.s_net). 43 */ 44 if (ro == 0) { 45 ro = &iproute; 46 bzero((caddr_t)ro, sizeof (*ro)); 47 } 48 if (ro->ro_rt == 0) { 49 ro->ro_dst.sa_family = AF_INET; 50 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = ip->ip_dst; 51 rtalloc(ro); 52 } 53 if (ro->ro_rt == 0 || (ifp = ro->ro_rt->rt_ifp) == 0) { 54 printf("no route to %x (from %x, len %d)\n", 55 ip->ip_dst.s_addr, ip->ip_src.s_addr, ip->ip_len); 56 goto bad; 57 } 58 dst = ro->ro_rt->rt_flags&RTF_DIRECT ? 59 (struct sockaddr *)&ro->ro_dst : &ro->ro_rt->rt_gateway; 60 if (ro == &iproute) 61 RTFREE(ro->ro_rt); 62 if (!allowbroadcast && (ifp->if_flags & IFF_BROADCAST)) { 63 struct sockaddr_in *sin; 64 65 sin = (struct sockaddr_in *)&ifp->if_broadaddr; 66 if (sin->sin_addr.s_addr == ip->ip_dst.s_addr) 67 goto bad; 68 } 69 70 /* 71 * If small enough for interface, can just send directly. 72 */ 73 if (ip->ip_len <= ifp->if_mtu) { 74 #if vax 75 ip->ip_len = htons((u_short)ip->ip_len); 76 ip->ip_off = htons((u_short)ip->ip_off); 77 #endif 78 ip->ip_sum = 0; 79 ip->ip_sum = in_cksum(m, hlen); 80 ro->ro_rt->rt_use++; 81 return ((*ifp->if_output)(ifp, m, dst)); 82 } 83 84 /* 85 * Too large for interface; fragment if possible. 86 * Must be able to put at least 8 bytes per fragment. 87 */ 88 if (ip->ip_off & IP_DF) 89 goto bad; 90 len = (ifp->if_mtu - hlen) &~ 7; 91 if (len < 8) 92 goto bad; 93 94 /* 95 * Discard IP header from logical mbuf for m_copy's sake. 96 * Loop through length of segment, make a copy of each 97 * part and output. 98 */ 99 m->m_len -= sizeof (struct ip); 100 m->m_off += sizeof (struct ip); 101 for (off = 0; off < ip->ip_len-hlen; off += len) { 102 struct mbuf *mh = m_get(M_DONTWAIT); 103 struct ip *mhip; 104 105 if (mh == 0) 106 goto bad; 107 mh->m_off = MMAXOFF - hlen; 108 mhip = mtod(mh, struct ip *); 109 *mhip = *ip; 110 if (hlen > sizeof (struct ip)) { 111 int olen = ip_optcopy(ip, mhip, off); 112 mh->m_len = sizeof (struct ip) + olen; 113 } else 114 mh->m_len = sizeof (struct ip); 115 mhip->ip_off = off >> 3; 116 if (off + len >= ip->ip_len-hlen) 117 len = mhip->ip_len = ip->ip_len - hlen - off; 118 else { 119 mhip->ip_len = len; 120 mhip->ip_off |= IP_MF; 121 } 122 mhip->ip_len += sizeof (struct ip); 123 #if vax 124 mhip->ip_len = htons((u_short)mhip->ip_len); 125 #endif 126 mh->m_next = m_copy(m, off, len); 127 if (mh->m_next == 0) { 128 (void) m_free(mh); 129 goto bad; 130 } 131 #if vax 132 mhip->ip_off = htons((u_short)mhip->ip_off); 133 #endif 134 mhip->ip_sum = 0; 135 mhip->ip_sum = in_cksum(mh, hlen); 136 ro->ro_rt->rt_use++; 137 if ((*ifp->if_output)(ifp, mh, dst) == 0) 138 goto bad; 139 } 140 m_freem(m); 141 return (1); 142 bad: 143 m_freem(m); 144 return (0); 145 } 146 147 /* 148 * Copy options from ip to jp. 149 * If off is 0 all options are copied 150 * otherwise copy selectively. 151 */ 152 ip_optcopy(ip, jp, off) 153 struct ip *ip, *jp; 154 int off; 155 { 156 register u_char *cp, *dp; 157 int opt, optlen, cnt; 158 159 COUNT(IP_OPTCOPY); 160 cp = (u_char *)(ip + 1); 161 dp = (u_char *)(jp + 1); 162 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 163 for (; cnt > 0; cnt -= optlen, cp += optlen) { 164 opt = cp[0]; 165 if (opt == IPOPT_EOL) 166 break; 167 if (opt == IPOPT_NOP) 168 optlen = 1; 169 else 170 optlen = cp[1]; 171 if (optlen > cnt) /* XXX */ 172 optlen = cnt; /* XXX */ 173 if (off == 0 || IPOPT_COPIED(opt)) { 174 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 175 dp += optlen; 176 } 177 } 178 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 179 *dp++ = IPOPT_EOL; 180 return (optlen); 181 } 182