diff options
Diffstat (limited to 'sys/netinet/ip_icmp.c')
| -rw-r--r-- | sys/netinet/ip_icmp.c | 878 |
1 files changed, 878 insertions, 0 deletions
diff --git a/sys/netinet/ip_icmp.c b/sys/netinet/ip_icmp.c new file mode 100644 index 0000000..ddb95f0 --- /dev/null +++ b/sys/netinet/ip_icmp.c @@ -0,0 +1,878 @@ +/* + * Copyright (c) 1982, 1986, 1988, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94 + * $FreeBSD$ + */ + +#include "opt_ipsec.h" + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/mbuf.h> +#include <sys/protosw.h> +#include <sys/socket.h> +#include <sys/time.h> +#include <sys/kernel.h> +#include <sys/sysctl.h> + +#include <net/if.h> +#include <net/route.h> + +#define _IP_VHL +#include <netinet/in.h> +#include <netinet/in_systm.h> +#include <netinet/in_var.h> +#include <netinet/ip.h> +#include <netinet/ip_icmp.h> +#include <netinet/ip_var.h> +#include <netinet/icmp_var.h> + +#ifdef IPSEC +#include <netinet6/ipsec.h> +#include <netkey/key.h> +#endif + +#include "faith.h" +#if defined(NFAITH) && NFAITH > 0 +#include <net/if_types.h> +#endif + +#include <machine/in_cksum.h> + +/* + * ICMP routines: error generation, receive packet processing, and + * routines to turnaround packets back to the originator, and + * host table maintenance routines. + */ + +static struct icmpstat icmpstat; +SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RD, + &icmpstat, icmpstat, ""); + +static int icmpmaskrepl = 0; +SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW, + &icmpmaskrepl, 0, ""); + +static int drop_redirect = 0; +SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW, + &drop_redirect, 0, ""); + +static int log_redirect = 0; +SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW, + &log_redirect, 0, ""); + +static int icmplim = 200; +SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW, + &icmplim, 0, ""); + +static int icmplim_output = 1; +SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW, + &icmplim_output, 0, ""); + +/* + * ICMP broadcast echo sysctl + */ + +static int icmpbmcastecho = 0; +SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW, + &icmpbmcastecho, 0, ""); + + +#ifdef ICMPPRINTFS +int icmpprintfs = 0; +#endif + +static void icmp_reflect __P((struct mbuf *)); +static void icmp_send __P((struct mbuf *, struct mbuf *)); +static int ip_next_mtu __P((int, int)); + +extern struct protosw inetsw[]; + +/* + * Generate an error packet of type error + * in response to bad packet ip. + */ +void +icmp_error(n, type, code, dest, destifp) + struct mbuf *n; + int type, code; + n_long dest; + struct ifnet *destifp; +{ + register struct ip *oip = mtod(n, struct ip *), *nip; + register unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2; + register struct icmp *icp; + register struct mbuf *m; + unsigned icmplen; + +#ifdef ICMPPRINTFS + if (icmpprintfs) + printf("icmp_error(%p, %x, %d)\n", oip, type, code); +#endif + if (type != ICMP_REDIRECT) + icmpstat.icps_error++; + /* + * Don't send error if not the first fragment of message. + * Don't error if the old packet protocol was ICMP + * error message, only known informational types. + */ + if (oip->ip_off &~ (IP_MF|IP_DF)) + goto freeit; + if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && + n->m_len >= oiplen + ICMP_MINLEN && + !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { + icmpstat.icps_oldicmp++; + goto freeit; + } + /* Don't send error in response to a multicast or broadcast packet */ + if (n->m_flags & (M_BCAST|M_MCAST)) + goto freeit; + /* + * First, formulate icmp message + */ + m = m_gethdr(M_DONTWAIT, MT_HEADER); + if (m == NULL) + goto freeit; + icmplen = min(oiplen + 8, oip->ip_len); + if (icmplen < sizeof(struct ip)) + panic("icmp_error: bad length"); + m->m_len = icmplen + ICMP_MINLEN; + MH_ALIGN(m, m->m_len); + icp = mtod(m, struct icmp *); + if ((u_int)type > ICMP_MAXTYPE) + panic("icmp_error"); + icmpstat.icps_outhist[type]++; + icp->icmp_type = type; + if (type == ICMP_REDIRECT) + icp->icmp_gwaddr.s_addr = dest; + else { + icp->icmp_void = 0; + /* + * The following assignments assume an overlay with the + * zeroed icmp_void field. + */ + if (type == ICMP_PARAMPROB) { + icp->icmp_pptr = code; + code = 0; + } else if (type == ICMP_UNREACH && + code == ICMP_UNREACH_NEEDFRAG && destifp) { + icp->icmp_nextmtu = htons(destifp->if_mtu); + } + } + + icp->icmp_code = code; + m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip); + nip = &icp->icmp_ip; + + /* + * Convert fields to network representation. + */ + HTONS(nip->ip_len); + HTONS(nip->ip_off); + + /* + * Now, copy old ip header (without options) + * in front of icmp message. + */ + if (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_len = m->m_len; + nip->ip_vhl = IP_VHL_BORING; + nip->ip_p = IPPROTO_ICMP; + nip->ip_tos = 0; + icmp_reflect(m); + +freeit: + m_freem(n); +} + +static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; +static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; +static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; + +/* + * Process a received ICMP message. + */ +void +icmp_input(m, off, proto) + register struct mbuf *m; + int off, proto; +{ + int hlen = off; + register struct icmp *icp; + register struct ip *ip = mtod(m, struct ip *); + int icmplen = ip->ip_len; + register int i; + struct in_ifaddr *ia; + void (*ctlfunc) __P((int, struct sockaddr *, void *)); + int code; + + /* + * Locate icmp structure in mbuf, and check + * that not corrupted and of at least minimum length. + */ +#ifdef ICMPPRINTFS + if (icmpprintfs) { + char buf[4 * sizeof "123"]; + strcpy(buf, inet_ntoa(ip->ip_src)); + printf("icmp_input from %s to %s, len %d\n", + buf, inet_ntoa(ip->ip_dst), icmplen); + } +#endif + if (icmplen < ICMP_MINLEN) { + icmpstat.icps_tooshort++; + goto freeit; + } + i = hlen + min(icmplen, ICMP_ADVLENMIN); + if (m->m_len < i && (m = m_pullup(m, i)) == 0) { + icmpstat.icps_tooshort++; + return; + } + ip = mtod(m, struct ip *); + m->m_len -= hlen; + m->m_data += hlen; + icp = mtod(m, struct icmp *); + if (in_cksum(m, icmplen)) { + icmpstat.icps_checksum++; + goto freeit; + } + m->m_len += hlen; + m->m_data -= hlen; + +#if defined(NFAITH) && 0 < NFAITH + if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) { + /* + * Deliver very specific ICMP type only. + */ + switch (icp->icmp_type) { + case ICMP_UNREACH: + case ICMP_TIMXCEED: + break; + default: + goto freeit; + } + } +#endif + +#ifdef ICMPPRINTFS + if (icmpprintfs) + printf("icmp_input, type %d code %d\n", icp->icmp_type, + icp->icmp_code); +#endif + +#ifdef IPSEC + /* drop it if it does not match the policy */ + /* XXX Is there meaning of check in here ? */ + if (ipsec4_in_reject(m, NULL)) { + ipsecstat.in_polvio++; + goto freeit; + } +#endif + + /* + * Message type specific processing. + */ + if (icp->icmp_type > ICMP_MAXTYPE) + goto raw; + icmpstat.icps_inhist[icp->icmp_type]++; + code = icp->icmp_code; + switch (icp->icmp_type) { + + case ICMP_UNREACH: + switch (code) { + case ICMP_UNREACH_NET: + case ICMP_UNREACH_HOST: + case ICMP_UNREACH_SRCFAIL: + case ICMP_UNREACH_NET_UNKNOWN: + case ICMP_UNREACH_HOST_UNKNOWN: + case ICMP_UNREACH_ISOLATED: + case ICMP_UNREACH_TOSNET: + case ICMP_UNREACH_TOSHOST: + case ICMP_UNREACH_HOST_PRECEDENCE: + case ICMP_UNREACH_PRECEDENCE_CUTOFF: + code = PRC_UNREACH_NET; + break; + + case ICMP_UNREACH_NEEDFRAG: + code = PRC_MSGSIZE; + break; + + /* + * RFC 1122, Sections 3.2.2.1 and 4.2.3.9. + * Treat subcodes 2,3 as immediate RST + */ + case ICMP_UNREACH_PROTOCOL: + case ICMP_UNREACH_PORT: + code = PRC_UNREACH_PORT; + break; + + case ICMP_UNREACH_NET_PROHIB: + case ICMP_UNREACH_HOST_PROHIB: + case ICMP_UNREACH_FILTER_PROHIB: + code = PRC_UNREACH_ADMIN_PROHIB; + break; + + default: + goto badcode; + } + goto deliver; + + case ICMP_TIMXCEED: + if (code > 1) + goto badcode; + code += PRC_TIMXCEED_INTRANS; + goto deliver; + + case ICMP_PARAMPROB: + if (code > 1) + goto badcode; + code = PRC_PARAMPROB; + goto deliver; + + case ICMP_SOURCEQUENCH: + if (code) + goto badcode; + code = PRC_QUENCH; + deliver: + /* + * Problem with datagram; advise higher level routines. + */ + if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || + IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { + icmpstat.icps_badlen++; + goto freeit; + } + NTOHS(icp->icmp_ip.ip_len); + /* Discard ICMP's in response to multicast packets */ + if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr))) + goto badcode; +#ifdef ICMPPRINTFS + if (icmpprintfs) + printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); +#endif + icmpsrc.sin_addr = icp->icmp_ip.ip_dst; +#if 1 + /* + * MTU discovery: + * If we got a needfrag and there is a host route to the + * original destination, and the MTU is not locked, then + * set the MTU in the route to the suggested new value + * (if given) and then notify as usual. The ULPs will + * notice that the MTU has changed and adapt accordingly. + * If no new MTU was suggested, then we guess a new one + * less than the current value. If the new MTU is + * unreasonably small (arbitrarily set at 296), then + * we reset the MTU to the interface value and enable the + * lock bit, indicating that we are no longer doing MTU + * discovery. + */ + if (code == PRC_MSGSIZE) { + struct rtentry *rt; + int mtu; + + rt = rtalloc1((struct sockaddr *)&icmpsrc, 0, + RTF_CLONING | RTF_PRCLONING); + if (rt && (rt->rt_flags & RTF_HOST) + && !(rt->rt_rmx.rmx_locks & RTV_MTU)) { + mtu = ntohs(icp->icmp_nextmtu); + if (!mtu) + mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu, + 1); +#ifdef DEBUG_MTUDISC + printf("MTU for %s reduced to %d\n", + inet_ntoa(icmpsrc.sin_addr), mtu); +#endif + if (mtu < 296) { + /* rt->rt_rmx.rmx_mtu = + rt->rt_ifp->if_mtu; */ + rt->rt_rmx.rmx_locks |= RTV_MTU; + } else if (rt->rt_rmx.rmx_mtu > mtu) { + rt->rt_rmx.rmx_mtu = mtu; + } + } + if (rt) + RTFREE(rt); + } + +#endif + /* + * XXX if the packet contains [IPv4 AH TCP], we can't make a + * notification to TCP layer. + */ + ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; + if (ctlfunc) + (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, + (void *)&icp->icmp_ip); + break; + + badcode: + icmpstat.icps_badcode++; + break; + + case ICMP_ECHO: + if (!icmpbmcastecho + && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { + icmpstat.icps_bmcastecho++; + break; + } + icp->icmp_type = ICMP_ECHOREPLY; + if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0) + goto freeit; + else + goto reflect; + + case ICMP_TSTAMP: + if (!icmpbmcastecho + && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { + icmpstat.icps_bmcasttstamp++; + break; + } + if (icmplen < ICMP_TSLEN) { + icmpstat.icps_badlen++; + break; + } + icp->icmp_type = ICMP_TSTAMPREPLY; + icp->icmp_rtime = iptime(); + icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ + if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0) + goto freeit; + else + goto reflect; + + case ICMP_MASKREQ: +#define satosin(sa) ((struct sockaddr_in *)(sa)) + if (icmpmaskrepl == 0) + break; + /* + * We are not able to respond with all ones broadcast + * unless we receive it over a point-to-point interface. + */ + if (icmplen < ICMP_MASKLEN) + break; + switch (ip->ip_dst.s_addr) { + + case INADDR_BROADCAST: + case INADDR_ANY: + icmpdst.sin_addr = ip->ip_src; + break; + + default: + icmpdst.sin_addr = ip->ip_dst; + } + ia = (struct in_ifaddr *)ifaof_ifpforaddr( + (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); + if (ia == 0) + break; + if (ia->ia_ifp == 0) + break; + icp->icmp_type = ICMP_MASKREPLY; + icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; + if (ip->ip_src.s_addr == 0) { + if (ia->ia_ifp->if_flags & IFF_BROADCAST) + ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; + else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) + ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; + } +reflect: + ip->ip_len += hlen; /* since ip_input deducts this */ + icmpstat.icps_reflect++; + icmpstat.icps_outhist[icp->icmp_type]++; + icmp_reflect(m); + return; + + case ICMP_REDIRECT: + if (log_redirect) { + u_long src, dst, gw; + + src = ntohl(ip->ip_src.s_addr); + dst = ntohl(icp->icmp_ip.ip_dst.s_addr); + gw = ntohl(icp->icmp_gwaddr.s_addr); + printf("icmp redirect from %d.%d.%d.%d: " + "%d.%d.%d.%d => %d.%d.%d.%d\n", + (int)(src >> 24), (int)((src >> 16) & 0xff), + (int)((src >> 8) & 0xff), (int)(src & 0xff), + (int)(dst >> 24), (int)((dst >> 16) & 0xff), + (int)((dst >> 8) & 0xff), (int)(dst & 0xff), + (int)(gw >> 24), (int)((gw >> 16) & 0xff), + (int)((gw >> 8) & 0xff), (int)(gw & 0xff)); + } + if (drop_redirect) + break; + if (code > 3) + goto badcode; + if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || + IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { + icmpstat.icps_badlen++; + break; + } + /* + * Short circuit routing redirects to force + * immediate change in the kernel's routing + * tables. The message is also handed to anyone + * listening on a raw socket (e.g. the routing + * daemon for use in updating its tables). + */ + icmpgw.sin_addr = ip->ip_src; + icmpdst.sin_addr = icp->icmp_gwaddr; +#ifdef ICMPPRINTFS + if (icmpprintfs) { + char buf[4 * sizeof "123"]; + strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst)); + + printf("redirect dst %s to %s\n", + buf, inet_ntoa(icp->icmp_gwaddr)); + } +#endif + icmpsrc.sin_addr = icp->icmp_ip.ip_dst; + rtredirect((struct sockaddr *)&icmpsrc, + (struct sockaddr *)&icmpdst, + (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, + (struct sockaddr *)&icmpgw, (struct rtentry **)0); + pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); +#ifdef IPSEC + key_sa_routechange((struct sockaddr *)&icmpsrc); +#endif + break; + + /* + * No kernel processing for the following; + * just fall through to send to raw listener. + */ + case ICMP_ECHOREPLY: + case ICMP_ROUTERADVERT: + case ICMP_ROUTERSOLICIT: + case ICMP_TSTAMPREPLY: + case ICMP_IREQREPLY: + case ICMP_MASKREPLY: + default: + break; + } + +raw: + rip_input(m, off, proto); + return; + +freeit: + m_freem(m); +} + +/* + * Reflect the ip packet back to the source + */ +static void +icmp_reflect(m) + struct mbuf *m; +{ + register struct ip *ip = mtod(m, struct ip *); + register struct in_ifaddr *ia; + struct in_addr t; + struct mbuf *opts = 0; + int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); + + if (!in_canforward(ip->ip_src) && + ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) != + (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { + m_freem(m); /* Bad return address */ + goto done; /* Ip_output() will check for broadcast */ + } + t = ip->ip_dst; + ip->ip_dst = ip->ip_src; + /* + * If the incoming packet was addressed directly to us, + * use dst as the src for the reply. Otherwise (broadcast + * or anonymous), use the address which corresponds + * to the incoming interface. + */ + TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link) { + if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) + break; + if (ia->ia_ifp && (ia->ia_ifp->if_flags & IFF_BROADCAST) && + t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr) + break; + } + icmpdst.sin_addr = t; + if ((ia == (struct in_ifaddr *)0) && m->m_pkthdr.rcvif) + ia = (struct in_ifaddr *)ifaof_ifpforaddr( + (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); + /* + * The following happens if the packet was not addressed to us, + * and was received on an interface with no IP address. + */ + if (ia == (struct in_ifaddr *)0) + ia = TAILQ_FIRST(&in_ifaddrhead); + t = IA_SIN(ia)->sin_addr; + ip->ip_src = t; + ip->ip_ttl = ip_defttl; + + if (optlen > 0) { + register u_char *cp; + int opt, cnt; + u_int len; + + /* + * Retrieve any source routing from the incoming packet; + * add on any record-route or timestamp options. + */ + cp = (u_char *) (ip + 1); + if ((opts = ip_srcroute()) == 0 && + (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { + opts->m_len = sizeof(struct in_addr); + mtod(opts, struct in_addr *)->s_addr = 0; + } + if (opts) { +#ifdef ICMPPRINTFS + if (icmpprintfs) + printf("icmp_reflect optlen %d rt %d => ", + optlen, opts->m_len); +#endif + for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { + opt = cp[IPOPT_OPTVAL]; + if (opt == IPOPT_EOL) + break; + if (opt == IPOPT_NOP) + len = 1; + else { + if (cnt < IPOPT_OLEN + sizeof(*cp)) + break; + len = cp[IPOPT_OLEN]; + if (len < IPOPT_OLEN + sizeof(*cp) || + len > cnt) + break; + } + /* + * Should check for overflow, but it "can't happen" + */ + if (opt == IPOPT_RR || opt == IPOPT_TS || + opt == IPOPT_SECURITY) { + bcopy((caddr_t)cp, + mtod(opts, caddr_t) + opts->m_len, len); + opts->m_len += len; + } + } + /* Terminate & pad, if necessary */ + cnt = opts->m_len % 4; + if (cnt) { + for (; cnt < 4; cnt++) { + *(mtod(opts, caddr_t) + opts->m_len) = + IPOPT_EOL; + opts->m_len++; + } + } +#ifdef ICMPPRINTFS + if (icmpprintfs) + printf("%d\n", opts->m_len); +#endif + } + /* + * Now strip out original options by copying rest of first + * mbuf's data back, and adjust the IP length. + */ + ip->ip_len -= optlen; + ip->ip_vhl = IP_VHL_BORING; + m->m_len -= optlen; + if (m->m_flags & M_PKTHDR) + m->m_pkthdr.len -= optlen; + optlen += sizeof(struct ip); + bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), + (unsigned)(m->m_len - sizeof(struct ip))); + } + m->m_flags &= ~(M_BCAST|M_MCAST); + icmp_send(m, opts); +done: + if (opts) + (void)m_free(opts); +} + +/* + * Send an icmp packet back to the ip level, + * after supplying a checksum. + */ +static void +icmp_send(m, opts) + register struct mbuf *m; + struct mbuf *opts; +{ + register struct ip *ip = mtod(m, struct ip *); + register int hlen; + register struct icmp *icp; + struct route ro; + + hlen = IP_VHL_HL(ip->ip_vhl) << 2; + m->m_data += hlen; + m->m_len -= hlen; + icp = mtod(m, struct icmp *); + icp->icmp_cksum = 0; + icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); + m->m_data -= hlen; + m->m_len += hlen; + m->m_pkthdr.rcvif = (struct ifnet *)0; +#ifdef ICMPPRINTFS + if (icmpprintfs) { + char buf[4 * sizeof "123"]; + strcpy(buf, inet_ntoa(ip->ip_dst)); + printf("icmp_send dst %s src %s\n", + buf, inet_ntoa(ip->ip_src)); + } +#endif + bzero(&ro, sizeof ro); + (void) ip_output(m, opts, &ro, 0, NULL); + if (ro.ro_rt) + RTFREE(ro.ro_rt); +} + +n_time +iptime() +{ + struct timeval atv; + u_long t; + + getmicrotime(&atv); + t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; + return (htonl(t)); +} + +#if 1 +/* + * Return the next larger or smaller MTU plateau (table from RFC 1191) + * given current value MTU. If DIR is less than zero, a larger plateau + * is returned; otherwise, a smaller value is returned. + */ +static int +ip_next_mtu(mtu, dir) + int mtu; + int dir; +{ + static int mtutab[] = { + 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296, + 68, 0 + }; + int i; + + for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) { + if (mtu >= mtutab[i]) + break; + } + + if (dir < 0) { + if (i == 0) { + return 0; + } else { + return mtutab[i - 1]; + } + } else { + if (mtutab[i] == 0) { + return 0; + } else if(mtu > mtutab[i]) { + return mtutab[i]; + } else { + return mtutab[i + 1]; + } + } +} +#endif + + +/* + * badport_bandlim() - check for ICMP bandwidth limit + * + * Return 0 if it is ok to send an ICMP error response, -1 if we have + * hit our bandwidth limit and it is not ok. + * + * If icmplim is <= 0, the feature is disabled and 0 is returned. + * + * For now we separate the TCP and UDP subsystems w/ different 'which' + * values. We may eventually remove this separation (and simplify the + * code further). + * + * Note that the printing of the error message is delayed so we can + * properly print the icmp error rate that the system was trying to do + * (i.e. 22000/100 pps, etc...). This can cause long delays in printing + * the 'final' error, but it doesn't make sense to solve the printing + * delay with more complex code. + */ + +int +badport_bandlim(int which) +{ + static int lticks[BANDLIM_MAX + 1]; + static int lpackets[BANDLIM_MAX + 1]; + int dticks; + const char *bandlimittype[] = { + "Limiting icmp unreach response", + "Limiting icmp ping response", + "Limiting icmp tstamp response", + "Limiting closed port RST response", + "Limiting open port RST response" + }; + + /* + * Return ok status if feature disabled or argument out of + * ranage. + */ + + if (icmplim <= 0 || which > BANDLIM_MAX || which < 0) + return(0); + dticks = ticks - lticks[which]; + + /* + * reset stats when cumulative dt exceeds one second. + */ + + if ((unsigned int)dticks > hz) { + if (lpackets[which] > icmplim && icmplim_output) { + printf("%s from %d to %d packets per second\n", + bandlimittype[which], + lpackets[which], + icmplim + ); + } + lticks[which] = ticks; + lpackets[which] = 0; + } + + /* + * bump packet count + */ + + if (++lpackets[which] > icmplim) { + return(-1); + } + return(0); +} + |
