+
+ {
+ int mhlen, firstlen = len;
+ struct mbuf **mnext = &m->m_nextpkt;
+
+ /*
+ * Loop through length of segment after first fragment,
+ * make new header and copy data of each part and link onto chain.
+ */
+ m0 = m;
+ mhlen = sizeof (struct ip);
+ for (off = hlen + len; off < ip->ip_len; off += len) {
+ MGETHDR(m, M_DONTWAIT, MT_HEADER);
+ if (m == 0) {
+ error = ENOBUFS;
+ goto sendorfree;
+ }
+ m->m_data += max_linkhdr;
+ mhip = mtod(m, struct ip *);
+ *mhip = *ip;
+ if (hlen > sizeof (struct ip)) {
+ mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
+ mhip->ip_hl = mhlen >> 2;
+ }
+ m->m_len = mhlen;
+ mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
+ if (ip->ip_off & IP_MF)
+ mhip->ip_off |= IP_MF;
+ if (off + len >= ip->ip_len)
+ len = ip->ip_len - off;
+ else
+ mhip->ip_off |= IP_MF;
+ mhip->ip_len = htons((u_short)(len + mhlen));
+ m->m_next = m_copy(m0, off, len);
+ if (m->m_next == 0) {
+ error = ENOBUFS; /* ??? */
+ goto sendorfree;
+ }
+ m->m_pkthdr.len = mhlen + len;
+ m->m_pkthdr.rcvif = (struct ifnet *)0;
+ mhip->ip_off = htons((u_short)mhip->ip_off);
+ mhip->ip_sum = 0;
+ mhip->ip_sum = in_cksum(m, mhlen);
+ *mnext = m;
+ mnext = &m->m_nextpkt;
+ ipstat.ips_ofragments++;
+ }
+ /*
+ * Update first fragment by trimming what's been copied out
+ * and updating header, then send each fragment (in order).
+ */
+ m_adj(m0, hlen + firstlen - ip->ip_len);
+ m->m_pkthdr.len = hlen + firstlen;
+ ip->ip_len = htons((u_short)m->m_pkthdr.len);
+ ip->ip_off = htons((u_short)(ip->ip_off | IP_MF));
+ ip->ip_sum = 0;
+ ip->ip_sum = in_cksum(m0, hlen);
+sendorfree:
+ for (m = m0; m; m = m0) {
+ m0 = m->m_nextpkt;
+ m->m_nextpkt = 0;
+ if (error == 0)
+ error = (*ifp->if_output)(ifp, m,
+ (struct sockaddr *)dst);
+ else
+ m_freem(m);
+ }
+ }
+done:
+ if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt)
+ RTFREE(ro->ro_rt);
+ return (error);
+bad:
+ m_freem(m0);
+ goto done;
+}
+
+/*
+ * Insert IP options into preformed packet.
+ * Adjust IP destination as required for IP source routing,
+ * as indicated by a non-zero in_addr at the start of the options.
+ */
+struct mbuf *
+ip_insertoptions(m, opt, phlen)
+ register struct mbuf *m;
+ struct mbuf *opt;
+ int *phlen;
+{
+ register struct ipoption *p = mtod(opt, struct ipoption *);
+ struct mbuf *n;
+ register struct ip *ip = mtod(m, struct ip *);
+ unsigned optlen;
+
+ optlen = opt->m_len - sizeof(p->ipopt_dst);
+ if (p->ipopt_dst.s_addr)
+ ip->ip_dst = p->ipopt_dst;
+ if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
+ MGETHDR(n, M_DONTWAIT, MT_HEADER);
+ if (n == 0)
+ return (m);
+ n->m_pkthdr.len = m->m_pkthdr.len + optlen;
+ m->m_len -= sizeof(struct ip);
+ m->m_data += sizeof(struct ip);
+ n->m_next = m;
+ m = n;
+ m->m_len = optlen + sizeof(struct ip);
+ m->m_data += max_linkhdr;
+ bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
+ } else {
+ m->m_data -= optlen;
+ m->m_len += optlen;
+ m->m_pkthdr.len += optlen;
+ ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
+ }
+ ip = mtod(m, struct ip *);
+ bcopy((caddr_t)p->ipopt_list, (caddr_t)(ip + 1), (unsigned)optlen);
+ *phlen = sizeof(struct ip) + optlen;
+ ip->ip_len += optlen;
+ return (m);
+}
+
+/*
+ * Copy options from ip to jp,
+ * omitting those not copied during fragmentation.
+ */
+ip_optcopy(ip, jp)
+ struct ip *ip, *jp;
+{
+ register u_char *cp, *dp;
+ int opt, optlen, cnt;
+
+ cp = (u_char *)(ip + 1);
+ dp = (u_char *)(jp + 1);
+ cnt = (ip->ip_hl << 2) - sizeof (struct ip);
+ for (; cnt > 0; cnt -= optlen, cp += optlen) {
+ opt = cp[0];
+ if (opt == IPOPT_EOL)
+ break;
+ if (opt == IPOPT_NOP)
+ optlen = 1;
+ else
+ optlen = cp[IPOPT_OLEN];
+ /* bogus lengths should have been caught by ip_dooptions */
+ if (optlen > cnt)
+ optlen = cnt;
+ if (IPOPT_COPIED(opt)) {
+ bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen);
+ dp += optlen;
+ }
+ }
+ for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
+ *dp++ = IPOPT_EOL;
+ return (optlen);