diff options
Diffstat (limited to 'sys/netinet/if_ether.c')
-rw-r--r-- | sys/netinet/if_ether.c | 554 |
1 files changed, 554 insertions, 0 deletions
diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c new file mode 100644 index 0000000..41f07c0 --- /dev/null +++ b/sys/netinet/if_ether.c @@ -0,0 +1,554 @@ +/* + * 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. + * + * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 + */ + +/* + * Ethernet address resolution protocol. + * TODO: + * add "inuse/lock" bit (or ref. count) along with valid bit + */ + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/malloc.h> +#include <sys/mbuf.h> +#include <sys/socket.h> +#include <sys/time.h> +#include <sys/kernel.h> +#include <sys/errno.h> +#include <sys/ioctl.h> +#include <sys/syslog.h> + +#include <net/if.h> +#include <net/if_dl.h> +#include <net/route.h> + +#include <netinet/in.h> +#include <netinet/in_systm.h> +#include <netinet/in_var.h> +#include <netinet/ip.h> +#include <netinet/if_ether.h> + +#define SIN(s) ((struct sockaddr_in *)s) +#define SDL(s) ((struct sockaddr_dl *)s) +#define SRP(s) ((struct sockaddr_inarp *)s) + +/* + * ARP trailer negotiation. Trailer protocol is not IP specific, + * but ARP request/response use IP addresses. + */ +#define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL + + +/* timer values */ +int arpt_prune = (5*60*1); /* walk list every 5 minutes */ +int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ +int arpt_down = 20; /* once declared down, don't send for 20 secs */ +#define rt_expire rt_rmx.rmx_expire + +static void arprequest __P((struct arpcom *, u_long *, u_long *, u_char *)); +static void arptfree __P((struct llinfo_arp *)); +static void arptimer __P((void *)); +static struct llinfo_arp *arplookup __P((u_long, int, int)); +static void in_arpinput __P((struct mbuf *)); + +extern struct ifnet loif; +extern struct timeval time; +struct llinfo_arp llinfo_arp = {&llinfo_arp, &llinfo_arp}; +struct ifqueue arpintrq = {0, 0, 0, 50}; +int arp_inuse, arp_allocated, arp_intimer; +int arp_maxtries = 5; +int useloopback = 1; /* use loopback interface for local traffic */ +int arpinit_done = 0; + +/* + * Timeout routine. Age arp_tab entries periodically. + */ +/* ARGSUSED */ +static void +arptimer(ignored_arg) + void *ignored_arg; +{ + int s = splnet(); + register struct llinfo_arp *la = llinfo_arp.la_next; + + timeout(arptimer, (caddr_t)0, arpt_prune * hz); + while (la != &llinfo_arp) { + register struct rtentry *rt = la->la_rt; + la = la->la_next; + if (rt->rt_expire && rt->rt_expire <= time.tv_sec) + arptfree(la->la_prev); /* timer has expired, clear */ + } + splx(s); +} + +/* + * Parallel to llc_rtrequest. + */ +void +arp_rtrequest(req, rt, sa) + int req; + register struct rtentry *rt; + struct sockaddr *sa; +{ + register struct sockaddr *gate = rt->rt_gateway; + register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; + static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; + + if (!arpinit_done) { + arpinit_done = 1; + timeout(arptimer, (caddr_t)0, hz); + } + if (rt->rt_flags & RTF_GATEWAY) + return; + switch (req) { + + case RTM_ADD: + /* + * XXX: If this is a manually added route to interface + * such as older version of routed or gated might provide, + * restore cloning bit. + */ + if ((rt->rt_flags & RTF_HOST) == 0 && + SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) + rt->rt_flags |= RTF_CLONING; + if (rt->rt_flags & RTF_CLONING) { + /* + * Case 1: This route should come from a route to iface. + */ + rt_setgate(rt, rt_key(rt), + (struct sockaddr *)&null_sdl); + gate = rt->rt_gateway; + SDL(gate)->sdl_type = rt->rt_ifp->if_type; + SDL(gate)->sdl_index = rt->rt_ifp->if_index; + rt->rt_expire = time.tv_sec; + break; + } + /* Announce a new entry if requested. */ + if (rt->rt_flags & RTF_ANNOUNCE) + arprequest((struct arpcom *)rt->rt_ifp, + &SIN(rt_key(rt))->sin_addr.s_addr, + &SIN(rt_key(rt))->sin_addr.s_addr, + (u_char *)LLADDR(SDL(gate))); + /*FALLTHROUGH*/ + case RTM_RESOLVE: + if (gate->sa_family != AF_LINK || + gate->sa_len < sizeof(null_sdl)) { + log(LOG_DEBUG, "arp_rtrequest: bad gateway value"); + break; + } + SDL(gate)->sdl_type = rt->rt_ifp->if_type; + SDL(gate)->sdl_index = rt->rt_ifp->if_index; + if (la != 0) + break; /* This happens on a route change */ + /* + * Case 2: This route may come from cloning, or a manual route + * add with a LL address. + */ + R_Malloc(la, struct llinfo_arp *, sizeof(*la)); + rt->rt_llinfo = (caddr_t)la; + if (la == 0) { + log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); + break; + } + arp_inuse++, arp_allocated++; + Bzero(la, sizeof(*la)); + la->la_rt = rt; + rt->rt_flags |= RTF_LLINFO; + insque(la, &llinfo_arp); + if (SIN(rt_key(rt))->sin_addr.s_addr == + (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { + /* + * This test used to be + * if (loif.if_flags & IFF_UP) + * It allowed local traffic to be forced + * through the hardware by configuring the loopback down. + * However, it causes problems during network configuration + * for boards that can't receive packets they send. + * It is now necessary to clear "useloopback" and remove + * the route to force traffic out to the hardware. + */ + rt->rt_expire = 0; + Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, + LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); + if (useloopback) + rt->rt_ifp = &loif; + + } + break; + + case RTM_DELETE: + if (la == 0) + break; + arp_inuse--; + remque(la); + rt->rt_llinfo = 0; + rt->rt_flags &= ~RTF_LLINFO; + if (la->la_hold) + m_freem(la->la_hold); + Free((caddr_t)la); + } +} + +/* + * Broadcast an ARP packet, asking who has addr on interface ac. + */ +void +arpwhohas(ac, addr) + register struct arpcom *ac; + register struct in_addr *addr; +{ + arprequest(ac, &ac->ac_ipaddr.s_addr, &addr->s_addr, ac->ac_enaddr); +} + +/* + * Broadcast an ARP request. Caller specifies: + * - arp header source ip address + * - arp header target ip address + * - arp header source ethernet address + */ +static void +arprequest(ac, sip, tip, enaddr) + register struct arpcom *ac; + register u_long *sip, *tip; + register u_char *enaddr; +{ + register struct mbuf *m; + register struct ether_header *eh; + register struct ether_arp *ea; + struct sockaddr sa; + + if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) + return; + m->m_len = sizeof(*ea); + m->m_pkthdr.len = sizeof(*ea); + MH_ALIGN(m, sizeof(*ea)); + ea = mtod(m, struct ether_arp *); + eh = (struct ether_header *)sa.sa_data; + bzero((caddr_t)ea, sizeof (*ea)); + bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, + sizeof(eh->ether_dhost)); + eh->ether_type = ETHERTYPE_ARP; /* if_output will swap */ + ea->arp_hrd = htons(ARPHRD_ETHER); + ea->arp_pro = htons(ETHERTYPE_IP); + ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ + ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ + ea->arp_op = htons(ARPOP_REQUEST); + bcopy((caddr_t)enaddr, (caddr_t)ea->arp_sha, sizeof(ea->arp_sha)); + bcopy((caddr_t)sip, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa)); + bcopy((caddr_t)tip, (caddr_t)ea->arp_tpa, sizeof(ea->arp_tpa)); + sa.sa_family = AF_UNSPEC; + sa.sa_len = sizeof(sa); + (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); +} + +/* + * Resolve an IP address into an ethernet address. If success, + * desten is filled in. If there is no entry in arptab, + * set one up and broadcast a request for the IP address. + * Hold onto this mbuf and resend it once the address + * is finally resolved. A return value of 1 indicates + * that desten has been filled in and the packet should be sent + * normally; a 0 return indicates that the packet has been + * taken over here, either now or for later transmission. + */ +int +arpresolve(ac, rt, m, dst, desten) + register struct arpcom *ac; + register struct rtentry *rt; + struct mbuf *m; + register struct sockaddr *dst; + register u_char *desten; +{ + register struct llinfo_arp *la; + struct sockaddr_dl *sdl; + + if (m->m_flags & M_BCAST) { /* broadcast */ + bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten, + sizeof(etherbroadcastaddr)); + return (1); + } + if (m->m_flags & M_MCAST) { /* multicast */ + ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); + return(1); + } + if (rt) + la = (struct llinfo_arp *)rt->rt_llinfo; + else { + if (la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0)) + rt = la->la_rt; + } + if (la == 0 || rt == 0) { + log(LOG_DEBUG, "arpresolve: can't allocate llinfo"); + m_freem(m); + return (0); + } + sdl = SDL(rt->rt_gateway); + /* + * Check the address family and length is valid, the address + * is resolved; otherwise, try to resolve. + */ + if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && + sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { + bcopy(LLADDR(sdl), desten, sdl->sdl_alen); + return 1; + } + /* + * There is an arptab entry, but no ethernet address + * response yet. Replace the held mbuf with this + * latest one. + */ + if (la->la_hold) + m_freem(la->la_hold); + la->la_hold = m; + if (rt->rt_expire) { + rt->rt_flags &= ~RTF_REJECT; + if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { + rt->rt_expire = time.tv_sec; + if (la->la_asked++ < arp_maxtries) + arpwhohas(ac, &(SIN(dst)->sin_addr)); + else { + rt->rt_flags |= RTF_REJECT; + rt->rt_expire += arpt_down; + la->la_asked = 0; + } + + } + } + return (0); +} + +/* + * Common length and type checks are done here, + * then the protocol-specific routine is called. + */ +void +arpintr() +{ + register struct mbuf *m; + register struct arphdr *ar; + int s; + + while (arpintrq.ifq_head) { + s = splimp(); + IF_DEQUEUE(&arpintrq, m); + splx(s); + if (m == 0 || (m->m_flags & M_PKTHDR) == 0) + panic("arpintr"); + if (m->m_len >= sizeof(struct arphdr) && + (ar = mtod(m, struct arphdr *)) && + ntohs(ar->ar_hrd) == ARPHRD_ETHER && + m->m_len >= + sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln) + + switch (ntohs(ar->ar_pro)) { + + case ETHERTYPE_IP: + case ETHERTYPE_IPTRAILERS: + in_arpinput(m); + continue; + } + m_freem(m); + } +} + +/* + * ARP for Internet protocols on 10 Mb/s Ethernet. + * Algorithm is that given in RFC 826. + * In addition, a sanity check is performed on the sender + * protocol address, to catch impersonators. + * We no longer handle negotiations for use of trailer protocol: + * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent + * along with IP replies if we wanted trailers sent to us, + * and also sent them in response to IP replies. + * This allowed either end to announce the desire to receive + * trailer packets. + * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, + * but formerly didn't normally send requests. + */ +static void +in_arpinput(m) + struct mbuf *m; +{ + register struct ether_arp *ea; + register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; + struct ether_header *eh; + register struct llinfo_arp *la = 0; + register struct rtentry *rt; + struct in_ifaddr *ia, *maybe_ia = 0; + struct sockaddr_dl *sdl; + struct sockaddr sa; + struct in_addr isaddr, itaddr, myaddr; + int op; + + ea = mtod(m, struct ether_arp *); + op = ntohs(ea->arp_op); + bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof (isaddr)); + bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof (itaddr)); + for (ia = in_ifaddr; ia; ia = ia->ia_next) + if (ia->ia_ifp == &ac->ac_if) { + maybe_ia = ia; + if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || + (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) + break; + } + if (maybe_ia == 0) + goto out; + myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; + if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, + sizeof (ea->arp_sha))) + goto out; /* it's from me, ignore it. */ + if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, + sizeof (ea->arp_sha))) { + log(LOG_ERR, + "arp: ether address is broadcast for IP address %x!\n", + ntohl(isaddr.s_addr)); + goto out; + } + if (isaddr.s_addr == myaddr.s_addr) { + log(LOG_ERR, + "duplicate IP address %x!! sent from ethernet address: %s\n", + ntohl(isaddr.s_addr), ether_sprintf(ea->arp_sha)); + itaddr = myaddr; + goto reply; + } + la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); + if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { + if (sdl->sdl_alen && + bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) + log(LOG_INFO, "arp info overwritten for %x by %s\n", + isaddr.s_addr, ether_sprintf(ea->arp_sha)); + bcopy((caddr_t)ea->arp_sha, LLADDR(sdl), + sdl->sdl_alen = sizeof(ea->arp_sha)); + if (rt->rt_expire) + rt->rt_expire = time.tv_sec + arpt_keep; + rt->rt_flags &= ~RTF_REJECT; + la->la_asked = 0; + if (la->la_hold) { + (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, + rt_key(rt), rt); + la->la_hold = 0; + } + } +reply: + if (op != ARPOP_REQUEST) { + out: + m_freem(m); + return; + } + if (itaddr.s_addr == myaddr.s_addr) { + /* I am the target */ + bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha, + sizeof(ea->arp_sha)); + bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha, + sizeof(ea->arp_sha)); + } else { + la = arplookup(itaddr.s_addr, 0, SIN_PROXY); + if (la == NULL) + goto out; + rt = la->la_rt; + bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha, + sizeof(ea->arp_sha)); + sdl = SDL(rt->rt_gateway); + bcopy(LLADDR(sdl), (caddr_t)ea->arp_sha, sizeof(ea->arp_sha)); + } + + bcopy((caddr_t)ea->arp_spa, (caddr_t)ea->arp_tpa, sizeof(ea->arp_spa)); + bcopy((caddr_t)&itaddr, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa)); + ea->arp_op = htons(ARPOP_REPLY); + ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ + eh = (struct ether_header *)sa.sa_data; + bcopy((caddr_t)ea->arp_tha, (caddr_t)eh->ether_dhost, + sizeof(eh->ether_dhost)); + eh->ether_type = ETHERTYPE_ARP; + sa.sa_family = AF_UNSPEC; + sa.sa_len = sizeof(sa); + (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); + return; +} + +/* + * Free an arp entry. + */ +static void +arptfree(la) + register struct llinfo_arp *la; +{ + register struct rtentry *rt = la->la_rt; + register struct sockaddr_dl *sdl; + if (rt == 0) + panic("arptfree"); + if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && + sdl->sdl_family == AF_LINK) { + sdl->sdl_alen = 0; + la->la_asked = 0; + rt->rt_flags &= ~RTF_REJECT; + return; + } + rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), + 0, (struct rtentry **)0); +} +/* + * Lookup or enter a new address in arptab. + */ +static struct llinfo_arp * +arplookup(addr, create, proxy) + u_long addr; + int create, proxy; +{ + register struct rtentry *rt; + static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; + + sin.sin_addr.s_addr = addr; + sin.sin_other = proxy ? SIN_PROXY : 0; + rt = rtalloc1((struct sockaddr *)&sin, create); + if (rt == 0) + return (0); + rt->rt_refcnt--; + if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || + rt->rt_gateway->sa_family != AF_LINK) { + if (create) + log(LOG_DEBUG, "arptnew failed on %x\n", ntohl(addr)); + return (0); + } + return ((struct llinfo_arp *)rt->rt_llinfo); +} + +int +arpioctl(cmd, data) + int cmd; + caddr_t data; +{ + return (EOPNOTSUPP); +} |