diff options
Diffstat (limited to 'sys/netinet/ip_icmp.c')
| -rw-r--r-- | sys/netinet/ip_icmp.c | 68 |
1 files changed, 48 insertions, 20 deletions
diff --git a/sys/netinet/ip_icmp.c b/sys/netinet/ip_icmp.c index 31fb79a8d23..cc4eb966601 100644 --- a/sys/netinet/ip_icmp.c +++ b/sys/netinet/ip_icmp.c @@ -1,4 +1,4 @@ -/* $OpenBSD: ip_icmp.c,v 1.38 2001/06/19 00:48:23 deraadt Exp $ */ +/* $OpenBSD: ip_icmp.c,v 1.39 2001/06/29 18:08:39 provos Exp $ */ /* $NetBSD: ip_icmp.c,v 1.19 1996/02/13 23:42:22 christos Exp $ */ /* @@ -126,8 +126,8 @@ icmp_error(n, type, code, dest, destifp) register struct ip *oip = mtod(n, struct ip *), *nip; register unsigned oiplen = oip->ip_hl << 2; register struct icmp *icp; - struct mbuf *m, m0; - unsigned icmplen; + struct mbuf *m; + unsigned icmplen, mblen; #ifdef ICMPPRINTFS if (icmpprintfs) @@ -140,7 +140,7 @@ icmp_error(n, type, code, dest, destifp) * Don't error if the old packet protocol was ICMP * error message, only known informational types. */ - if (oip->ip_off &~ (IP_MF|IP_DF)) + if (oip->ip_off & IP_OFFMASK) goto freeit; if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && n->m_len >= oiplen + ICMP_MINLEN && @@ -163,12 +163,41 @@ icmp_error(n, type, code, dest, destifp) /* * Now, formulate icmp message */ + icmplen = oiplen + min(8, oip->ip_len); + /* + * Defend against mbuf chains shorter than oip->ip_len: + */ + mblen = 0; + for (m = n; m && (mblen < icmplen); m = m->m_next) + mblen += m->m_len; + icmplen = min(mblen, icmplen); + + /* + * As we are not required to return everything we have, + * we return whatever we can return at ease. + * + * Note that ICMP datagrams longer than 576 octets are out of spec + * according to RFC1812; + */ + + KASSERT(ICMP_MINLEN <= MCLBYTES); + + if (icmplen + ICMP_MINLEN > MCLBYTES) + icmplen = MCLBYTES - ICMP_MINLEN - sizeof (struct ip); + m = m_gethdr(M_DONTWAIT, MT_HEADER); + if (m && (sizeof (struct ip) + icmplen + ICMP_MINLEN > MHLEN)) { + MCLGET(m, M_DONTWAIT); + if ((m->m_flags & M_EXT) == 0) { + m_freem(m); + m = NULL; + } + } if (m == NULL) goto freeit; - icmplen = oiplen + min(8, oip->ip_len); m->m_len = icmplen + ICMP_MINLEN; - MH_ALIGN(m, m->m_len); + if ((m->m_flags & M_EXT) == 0) + MH_ALIGN(m, m->m_len); icp = mtod(m, struct icmp *); if ((u_int)type > ICMP_MAXTYPE) panic("icmp_error"); @@ -190,35 +219,34 @@ icmp_error(n, type, code, dest, destifp) icp->icmp_nextmtu = htons(destifp->if_mtu); } + HTONS(oip->ip_off); + HTONS(oip->ip_len); icp->icmp_code = code; - bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); + m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip); nip = &icp->icmp_ip; - nip->ip_off = htons(nip->ip_off); - nip->ip_len = htons(nip->ip_len); - - m0.m_next = NULL; /* correct nip->ip_sum */ - m0.m_data = (char *)nip; - m0.m_len = nip->ip_hl << 2; - nip->ip_sum = 0; - nip->ip_sum = in_cksum(&m0, nip->ip_hl << 2); /* * Now, copy old ip header (without options) * in front of icmp message. */ - if (m->m_data - sizeof(struct ip) < m->m_pktdat) + if ((m->m_flags & M_EXT) == 0 && + m->m_data - sizeof(struct ip) < m->m_pktdat) panic("icmp len"); m->m_data -= sizeof(struct ip); m->m_len += sizeof(struct ip); m->m_pkthdr.len = m->m_len; m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; nip = mtod(m, struct ip *); - bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip)); - nip->ip_off = htons(nip->ip_off); - nip->ip_len = m->m_len; + /* ip_v set in ip_output */ nip->ip_hl = sizeof(struct ip) >> 2; - nip->ip_p = IPPROTO_ICMP; nip->ip_tos = 0; + nip->ip_len = m->m_len; + /* ip_id set in ip_output */ + nip->ip_off = 0; + /* ip_ttl set in icmp_reflect */ + nip->ip_p = IPPROTO_ICMP; + nip->ip_src = oip->ip_src; + nip->ip_dst = oip->ip_dst; icmp_reflect(m); freeit: |