1 /* ip_output.c 1.26 82/03/15 */ 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 14 ip_output(m, opt, allowbroadcast) 15 struct mbuf *m; 16 struct mbuf *opt; 17 int allowbroadcast; 18 { 19 register struct ip *ip = mtod(m, struct ip *); 20 register struct ifnet *ifp; 21 int len, hlen = sizeof (struct ip), off; 22 23 COUNT(IP_OUTPUT); 24 if (opt) /* XXX */ 25 (void) m_free(opt); /* XXX */ 26 /* 27 * Fill in IP header. 28 */ 29 ip->ip_v = IPVERSION; 30 ip->ip_hl = hlen >> 2; 31 ip->ip_off &= IP_DF; 32 ip->ip_id = htons(ip_id++); 33 34 /* 35 * Find interface for this packet. 36 */ 37 ifp = if_ifonnetof(ip->ip_dst); 38 if (ifp == 0) { 39 ifp = if_gatewayfor(ip->ip_dst); 40 if (ifp == 0) 41 goto bad; 42 } 43 if (!allowbroadcast && ifp->if_broadaddr.s_addr != 0 && 44 ifp->if_broadaddr.s_addr == ip->ip_dst.s_addr) 45 goto bad; 46 47 /* 48 * If small enough for interface, can just send directly. 49 */ 50 if (ip->ip_len <= ifp->if_mtu) { 51 #if vax 52 ip->ip_len = htons((u_short)ip->ip_len); 53 ip->ip_off = htons((u_short)ip->ip_off); 54 #endif 55 ip->ip_sum = 0; 56 ip->ip_sum = in_cksum(m, hlen); 57 return ((*ifp->if_output)(ifp, m, PF_INET)); 58 } 59 60 /* 61 * Too large for interface; fragment if possible. 62 * Must be able to put at least 8 bytes per fragment. 63 */ 64 if (ip->ip_off & IP_DF) 65 goto bad; 66 len = (ifp->if_mtu - hlen) &~ 7; 67 if (len < 8) 68 goto bad; 69 70 /* 71 * Discard IP header from logical mbuf for m_copy's sake. 72 * Loop through length of segment, make a copy of each 73 * part and output. 74 */ 75 m->m_len -= sizeof (struct ip); 76 m->m_off += sizeof (struct ip); 77 for (off = 0; off < ip->ip_len-hlen; off += len) { 78 struct mbuf *mh = m_get(M_DONTWAIT); 79 struct ip *mhip; 80 81 if (mh == 0) 82 goto bad; 83 mh->m_off = MMAXOFF - hlen; 84 mhip = mtod(mh, struct ip *); 85 *mhip = *ip; 86 if (hlen > sizeof (struct ip)) { 87 int olen = ip_optcopy(ip, mhip, off); 88 mh->m_len = sizeof (struct ip) + olen; 89 } else 90 mh->m_len = sizeof (struct ip); 91 mhip->ip_off = off >> 3; 92 if (off + len >= ip->ip_len-hlen) 93 len = mhip->ip_len = ip->ip_len - hlen - off; 94 else { 95 mhip->ip_len = len; 96 mhip->ip_off |= IP_MF; 97 } 98 mhip->ip_len += sizeof (struct ip); 99 #if vax 100 mhip->ip_len = htons((u_short)mhip->ip_len); 101 #endif 102 mh->m_next = m_copy(m, off, len); 103 if (mh->m_next == 0) { 104 (void) m_free(mh); 105 goto bad; 106 } 107 #if vax 108 mhip->ip_off = htons((u_short)mhip->ip_off); 109 #endif 110 mhip->ip_sum = 0; 111 mhip->ip_sum = in_cksum(mh, hlen); 112 if ((*ifp->if_output)(ifp, mh, PF_INET) == 0) 113 goto bad; 114 } 115 m_freem(m); 116 return (1); 117 bad: 118 m_freem(m); 119 return (0); 120 } 121 122 /* 123 * Copy options from ip to jp. 124 * If off is 0 all options are copied 125 * otherwise copy selectively. 126 */ 127 ip_optcopy(ip, jp, off) 128 struct ip *ip, *jp; 129 int off; 130 { 131 register u_char *cp, *dp; 132 int opt, optlen, cnt; 133 134 COUNT(IP_OPTCOPY); 135 cp = (u_char *)(ip + 1); 136 dp = (u_char *)(jp + 1); 137 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 138 for (; cnt > 0; cnt -= optlen, cp += optlen) { 139 opt = cp[0]; 140 if (opt == IPOPT_EOL) 141 break; 142 if (opt == IPOPT_NOP) 143 optlen = 1; 144 else 145 optlen = cp[1]; 146 if (optlen > cnt) /* XXX */ 147 optlen = cnt; /* XXX */ 148 if (off == 0 || IPOPT_COPIED(opt)) { 149 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 150 dp += optlen; 151 } 152 } 153 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 154 *dp++ = IPOPT_EOL; 155 return (optlen); 156 } 157