1 /* ip_output.c 1.29 82/03/30 */ 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 call on route degenerates 42 * 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\n", ip->ip_dst.s_addr); 55 goto bad; 56 } 57 dst = ro->ro_rt->rt_flags&RTF_DIRECT ? 58 (struct sockaddr *)&ro->ro_dst : &ro->ro_rt->rt_gateway; 59 if (!allowbroadcast && (ifp->if_flags & IFF_BROADCAST)) { 60 struct sockaddr_in *sin; 61 62 sin = (struct sockaddr_in *)&ifp->if_broadaddr; 63 if (sin->sin_addr.s_addr == ip->ip_dst.s_addr) 64 goto bad; 65 } 66 67 /* 68 * If small enough for interface, can just send directly. 69 */ 70 if (ip->ip_len <= ifp->if_mtu) { 71 #if vax 72 ip->ip_len = htons((u_short)ip->ip_len); 73 ip->ip_off = htons((u_short)ip->ip_off); 74 #endif 75 ip->ip_sum = 0; 76 ip->ip_sum = in_cksum(m, hlen); 77 return ((*ifp->if_output)(ifp, m, dst)); 78 } 79 80 /* 81 * Too large for interface; fragment if possible. 82 * Must be able to put at least 8 bytes per fragment. 83 */ 84 if (ip->ip_off & IP_DF) 85 goto bad; 86 len = (ifp->if_mtu - hlen) &~ 7; 87 if (len < 8) 88 goto bad; 89 90 /* 91 * Discard IP header from logical mbuf for m_copy's sake. 92 * Loop through length of segment, make a copy of each 93 * part and output. 94 */ 95 m->m_len -= sizeof (struct ip); 96 m->m_off += sizeof (struct ip); 97 for (off = 0; off < ip->ip_len-hlen; off += len) { 98 struct mbuf *mh = m_get(M_DONTWAIT); 99 struct ip *mhip; 100 101 if (mh == 0) 102 goto bad; 103 mh->m_off = MMAXOFF - hlen; 104 mhip = mtod(mh, struct ip *); 105 *mhip = *ip; 106 if (hlen > sizeof (struct ip)) { 107 int olen = ip_optcopy(ip, mhip, off); 108 mh->m_len = sizeof (struct ip) + olen; 109 } else 110 mh->m_len = sizeof (struct ip); 111 mhip->ip_off = off >> 3; 112 if (off + len >= ip->ip_len-hlen) 113 len = mhip->ip_len = ip->ip_len - hlen - off; 114 else { 115 mhip->ip_len = len; 116 mhip->ip_off |= IP_MF; 117 } 118 mhip->ip_len += sizeof (struct ip); 119 #if vax 120 mhip->ip_len = htons((u_short)mhip->ip_len); 121 #endif 122 mh->m_next = m_copy(m, off, len); 123 if (mh->m_next == 0) { 124 (void) m_free(mh); 125 goto bad; 126 } 127 #if vax 128 mhip->ip_off = htons((u_short)mhip->ip_off); 129 #endif 130 mhip->ip_sum = 0; 131 mhip->ip_sum = in_cksum(mh, hlen); 132 if ((*ifp->if_output)(ifp, mh, dst) == 0) 133 goto bad; 134 } 135 m_freem(m); 136 return (1); 137 bad: 138 m_freem(m); 139 return (0); 140 } 141 142 /* 143 * Copy options from ip to jp. 144 * If off is 0 all options are copied 145 * otherwise copy selectively. 146 */ 147 ip_optcopy(ip, jp, off) 148 struct ip *ip, *jp; 149 int off; 150 { 151 register u_char *cp, *dp; 152 int opt, optlen, cnt; 153 154 COUNT(IP_OPTCOPY); 155 cp = (u_char *)(ip + 1); 156 dp = (u_char *)(jp + 1); 157 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 158 for (; cnt > 0; cnt -= optlen, cp += optlen) { 159 opt = cp[0]; 160 if (opt == IPOPT_EOL) 161 break; 162 if (opt == IPOPT_NOP) 163 optlen = 1; 164 else 165 optlen = cp[1]; 166 if (optlen > cnt) /* XXX */ 167 optlen = cnt; /* XXX */ 168 if (off == 0 || IPOPT_COPIED(opt)) { 169 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 170 dp += optlen; 171 } 172 } 173 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 174 *dp++ = IPOPT_EOL; 175 return (optlen); 176 } 177