/* * INET An implementation of the TCP/IP protocol suite for the LINUX * operating system. INET is implemented using the BSD Socket * interface as the means of communication with the user level. * * IPv4 Forwarding Information Base: FIB frontend. * * Version: $Id: fib_frontend.c,v 1.26 2001/10/31 21:55:54 davem Exp $ * * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/config.h> #include <linux/module.h> #include <asm/uaccess.h> #include <asm/system.h> #include <linux/bitops.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/mm.h> #include <linux/string.h> #include <linux/socket.h> #include <linux/sockios.h> #include <linux/errno.h> #include <linux/in.h> #include <linux/inet.h> #include <linux/netdevice.h> #include <linux/if_arp.h> #include <linux/skbuff.h> #include <linux/netlink.h> #include <linux/init.h> #include <net/ip.h> #include <net/protocol.h> #include <net/route.h> #include <net/tcp.h> #include <net/sock.h> #include <net/icmp.h> #include <net/arp.h> #include <net/ip_fib.h> #define FFprint(a...) printk(KERN_DEBUG a) #ifndef CONFIG_IP_MULTIPLE_TABLES #define RT_TABLE_MIN RT_TABLE_MAIN struct fib_table *ip_fib_local_table; struct fib_table *ip_fib_main_table; #else #define RT_TABLE_MIN 1 struct fib_table *fib_tables[RT_TABLE_MAX+1]; struct fib_table *__fib_new_table(int id) { struct fib_table *tb; tb = fib_hash_init(id); if (!tb) return NULL; fib_tables[id] = tb; return tb; } #endif /* CONFIG_IP_MULTIPLE_TABLES */ static void fib_flush(void) { int flushed = 0; #ifdef CONFIG_IP_MULTIPLE_TABLES struct fib_table *tb; int id; for (id = RT_TABLE_MAX; id>0; id--) { if ((tb = fib_get_table(id))==NULL) continue; flushed += tb->tb_flush(tb); } #else /* CONFIG_IP_MULTIPLE_TABLES */ flushed += ip_fib_main_table->tb_flush(ip_fib_main_table); flushed += ip_fib_local_table->tb_flush(ip_fib_local_table); #endif /* CONFIG_IP_MULTIPLE_TABLES */ if (flushed) rt_cache_flush(-1); } /* * Find the first device with a given source address. */ struct net_device * ip_dev_find(u32 addr) { struct flowi fl = { .nl_u = { .ip4_u = { .daddr = addr } } }; struct fib_result res; struct net_device *dev = NULL; #ifdef CONFIG_IP_MULTIPLE_TABLES res.r = NULL; #endif if (!ip_fib_local_table || ip_fib_local_table->tb_lookup(ip_fib_local_table, &fl, &res)) return NULL; if (res.type != RTN_LOCAL) goto out; dev = FIB_RES_DEV(res); if (dev) dev_hold(dev); out: fib_res_put(&res); return dev; } unsigned inet_addr_type(u32 addr) { struct flowi fl = { .nl_u = { .ip4_u = { .daddr = addr } } }; struct fib_result res; unsigned ret = RTN_BROADCAST; if (ZERONET(addr) || BADCLASS(addr)) return RTN_BROADCAST; if (MULTICAST(addr)) return RTN_MULTICAST; #ifdef CONFIG_IP_MULTIPLE_TABLES res.r = NULL; #endif if (ip_fib_local_table) { ret = RTN_UNICAST; if (!ip_fib_local_table->tb_lookup(ip_fib_local_table, &fl, &res)) { ret = res.type; fib_res_put(&res); } } return ret; } /* Given (packet source, input interface) and optional (dst, oif, tos): - (main) check, that source is valid i.e. not broadcast or our local address. - figure out what "logical" interface this packet arrived and calculate "specific destination" address. - check, that packet arrived from expected physical interface. */ int fib_validate_source(u32 src, u32 dst, u8 tos, int oif, struct net_device *dev, u32 *spec_dst, u32 *itag) { struct in_device *in_dev; struct flowi fl = { .nl_u = { .ip4_u = { .daddr = src, .saddr = dst, .tos = tos } }, .iif = oif }; struct fib_result res; int no_addr, rpf; int ret; no_addr = rpf = 0; rcu_read_lock(); in_dev = __in_dev_get_rcu(dev); if (in_dev) { no_addr = in_dev->ifa_list == NULL; rpf = IN_DEV_RPFILTER(in_dev); } rcu_read_unlock(); if (in_dev == NULL) goto e_inval; if (fib_lookup(&fl, &res)) goto last_resort; if (res.type != RTN_UNICAST) goto e_inval_res; *spec_dst = FIB_RES_PREFSRC(res); fib_combine_itag(itag, &res); #ifdef CONFIG_IP_ROUTE_MULTIPATH if (FIB_RES_DEV(res) == dev || res.fi->fib_nhs > 1) #else if (FIB_RES_DEV(res) == dev) #endif { ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST; fib_res_put(&res); return ret; } fib_res_put(&res); if (no_addr) goto last_resort; if (rpf) goto e_inval; fl.oif = dev->ifindex; ret = 0; if (fib_lookup(&fl, &res) == 0) { if (res.type == RTN_UNICAST) { *spec_dst = FIB_RES_PREFSRC(res); ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST; } fib_res_put(&res); } return ret; last_resort: if (rpf) goto e_inval; *spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE); *itag = 0; return 0; e_inval_res: fib_res_put(&res); e_inval: return -EINVAL; } #ifndef CONFIG_IP_NOSIOCRT /* * Handle IP routing ioctl calls. These are used to manipulate the routing tables */ int ip_rt_ioctl(unsigned int cmd, void __user *arg) { int err; struct kern_rta rta; struct rtentry r; struct { struct nlmsghdr nlh; struct rtmsg rtm; } req; switch (cmd) { case SIOCADDRT: /* Add a route */ case SIOCDELRT: /* Delete a route */ if (!capable(CAP_NET_ADMIN)) return -EPERM; if (copy_from_user(&r, arg, sizeof(struct rtentry))) return -EFAULT; rtnl_lock(); err = fib_convert_rtentry(cmd, &req.nlh, &req.rtm, &rta, &r); if (err == 0) { if (cmd == SIOCDELRT) { struct fib_table *tb = fib_get_table(req.rtm.rtm_table); err = -ESRCH; if (tb) err = tb->tb_delete(tb, &req.rtm, &rta, &req.nlh, NULL); } else { struct fib_table *tb = fib_new_table(req.rtm.rtm_table); err = -ENOBUFS; if (tb) err = tb->tb_insert(tb, &req.rtm, &rta, &req.nlh, NULL); } kfree(rta.rta_mx); } rtnl_unlock(); return err; } return -EINVAL; } #else int ip_rt_ioctl(unsigned int cmd, void *arg) { return -EINVAL; } #endif static int inet_check_attr(struct rtmsg *r, struct rtattr **rta) { int i; for (i=1; i<=RTA_MAX; i++) { struct rtattr *attr = rta[i-1]; if (attr) { if (RTA_PAYLOAD(attr) < 4) return -EINVAL; if (i != RTA_MULTIPATH && i != RTA_METRICS) rta[i-1] = (struct rtattr*)RTA_DATA(attr); } } return 0; } int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) { struct fib_table * tb; struct rtattr **rta = arg; struct rtmsg *r = NLMSG_DATA(nlh); if (inet_check_attr(r, rta)) return -EINVAL; tb = fib_get_table(r->rtm_table); if (tb) return tb->tb_delete(tb, r, (struct kern_rta*)rta, nlh, &NETLINK_CB(skb)); return -ESRCH; } int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) { struct fib_table * tb; struct rtattr **rta = arg; struct rtmsg *r = NLMSG_DATA(nlh); if (inet_check_attr(r, rta)) return -EINVAL; tb = fib_new_table(r->rtm_table); if (tb) return tb->tb_insert(tb, r, (struct kern_rta*)rta, nlh, &NETLINK_CB(skb)); return -ENOBUFS; } int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) { int t; int s_t; struct fib_table *tb; if (NLMSG_PAYLOAD(cb->nlh, 0) >= sizeof(struct rtmsg) && ((struct rtmsg*)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED) return ip_rt_dump(skb, cb); s_t = cb->args[0]; if (s_t == 0) s_t = cb->args[0] = RT_TABLE_MIN; for (t=s_t; t<=RT_TABLE_MAX; t++) { if (t < s_t) continue; if (t > s_t) memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0])); if ((tb = fib_get_table(t))==NULL) continue; if (tb->tb_dump(tb, skb, cb) < 0) break; } cb->args[0] = t; return skb->len; } /* Prepare and feed intra-kernel routing request. Really, it should be netlink message, but :-( netlink can be not configured, so that we feed it directly to fib engine. It is legal, because all events occur only when netlink is already locked. */ static void fib_magic(int cmd, int type, u32 dst, int dst_len, struct in_ifaddr *ifa) { struct fib_table * tb; struct { struct nlmsghdr nlh; struct rtmsg rtm; } req; struct kern_rta rta; memset(&req.rtm, 0, sizeof(req.rtm)); memset(&rta, 0, sizeof(rta)); if (type == RTN_UNICAST) tb = fib_new_table(RT_TABLE_MAIN); else tb = fib_new_table(RT_TABLE_LOCAL); if (tb == NULL) return; req.nlh.nlmsg_len = sizeof(req); req.nlh.nlmsg_type = cmd; req.nlh.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_APPEND; req.nlh.nlmsg_pid = 0; req.nlh.nlmsg_seq = 0; req.rtm.rtm_dst_len = dst_len; req.rtm.rtm_table = tb->tb_id; req.rtm.rtm_protocol = RTPROT_KERNEL; req.rtm.rtm_scope = (type != RTN_LOCAL ? RT_SCOPE_LINK : RT_SCOPE_HOST); req.rtm.rtm_type = type; rta.rta_dst = &dst; rta.rta_prefsrc = &ifa->ifa_local; rta.rta_oif = &ifa->ifa_dev->dev->ifindex; if (cmd == RTM_NEWROUTE) tb->tb_insert(tb, &req.rtm, &rta, &req.nlh, NULL); else tb->tb_delete(tb, &req.rtm, &rta, &req.nlh, NULL); } void fib_add_ifaddr(struct in_ifaddr *ifa) { struct in_device *in_dev = ifa->ifa_dev; struct net_device *dev = in_dev->dev; struct in_ifaddr *prim = ifa; u32 mask = ifa->ifa_mask; u32 addr = ifa->ifa_local; u32 prefix = ifa->ifa_address&mask; if (ifa->ifa_flags&IFA_F_SECONDARY) { prim = inet_ifa_byprefix(in_dev, prefix, mask); if (prim == NULL) { printk(KERN_DEBUG "fib_add_ifaddr: bug: prim == NULL\n"); return; } } fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim); if (!(dev->flags&IFF_UP)) return; /* Add broadcast address, if it is explicitly assigned. */ if (ifa->ifa_broadcast && ifa->ifa_broadcast != 0xFFFFFFFF) fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim); if (!ZERONET(prefix) && !(ifa->ifa_flags&IFA_F_SECONDARY) && (prefix != addr || ifa->ifa_prefixlen < 32)) { fib_magic(RTM_NEWROUTE, dev->flags&IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST, prefix, ifa->ifa_prefixlen, prim); /* Add network specific broadcasts, when it takes a sense */ if (ifa->ifa_prefixlen < 31) { fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim); fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix|~mask, 32, prim); } } } static void fib_del_ifaddr(struct in_ifaddr *ifa) { struct in_device *in_dev = ifa->ifa_dev; struct net_device *dev = in_dev->dev; struct in_ifaddr *ifa1; struct in_ifaddr *prim = ifa; u32 brd = ifa->ifa_address|~ifa->ifa_mask; u32 any = ifa->ifa_address&ifa->ifa_mask; #define LOCAL_OK 1 #define BRD_OK 2 #define BRD0_OK 4 #define BRD1_OK 8 unsigned ok = 0; if (!(ifa->ifa_flags&IFA_F_SECONDARY)) fib_magic(RTM_DELROUTE, dev->flags&IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST, any, ifa->ifa_prefixlen, prim); else { prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask); if (prim == NULL) { printk(KERN_DEBUG "fib_del_ifaddr: bug: prim == NULL\n"); return; } } /* Deletion is more complicated than add. We should take care of not to delete too much :-) Scan address list to be sure that addresses are really gone. */ for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) { if (ifa->ifa_local == ifa1->ifa_local) ok |= LOCAL_OK; if (ifa->ifa_broadcast == ifa1->ifa_broadcast) ok |= BRD_OK; if (brd == ifa1->ifa_broadcast) ok |= BRD1_OK; if (any == ifa1->ifa_broadcast) ok |= BRD0_OK; } if (!(ok&BRD_OK)) fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim); if (!(ok&BRD1_OK)) fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim); if (!(ok&BRD0_OK)) fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim); if (!(ok&LOCAL_OK)) { fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim); /* Check, that this local address finally disappeared. */ if (inet_addr_type(ifa->ifa_local) != RTN_LOCAL) { /* And the last, but not the least thing. We must flush stray FIB entries. First of all, we scan fib_info list searching for stray nexthop entries, then ignite fib_flush. */ if (fib_sync_down(ifa->ifa_local, NULL, 0)) fib_flush(); } } #undef LOCAL_OK #undef BRD_OK #undef BRD0_OK #undef BRD1_OK } static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb ) { struct fib_result res; struct flowi fl = { .nl_u = { .ip4_u = { .daddr = frn->fl_addr, .fwmark = frn->fl_fwmark, .tos = frn->fl_tos, .scope = frn->fl_scope } } }; if (tb) { local_bh_disable(); frn->tb_id = tb->tb_id; frn->err = tb->tb_lookup(tb, &fl, &res); if (!frn->err) { frn->prefixlen = res.prefixlen; frn->nh_sel = res.nh_sel; frn->type = res.type; frn->scope = res.scope; } local_bh_enable(); } } static void nl_fib_input(struct sock *sk, int len) { struct sk_buff *skb = NULL; struct nlmsghdr *nlh = NULL; struct fib_result_nl *frn; int err; u32 pid; struct fib_table *tb; skb = skb_recv_datagram(sk, 0, 0, &err); nlh = (struct nlmsghdr *)skb->data; frn = (struct fib_result_nl *) NLMSG_DATA(nlh); tb = fib_get_table(frn->tb_id_in); nl_fib_lookup(frn, tb); pid = nlh->nlmsg_pid; /*pid of sending process */ NETLINK_CB(skb).pid = 0; /* from kernel */ NETLINK_CB(skb).dst_pid = pid; NETLINK_CB(skb).dst_group = 0; /* unicast */ netlink_unicast(sk, skb, pid, MSG_DONTWAIT); } static void nl_fib_lookup_init(void) { netlink_kernel_create(NETLINK_FIB_LOOKUP, 0, nl_fib_input, THIS_MODULE); } static void fib_disable_ip(struct net_device *dev, int force) { if (fib_sync_down(0, dev, force)) fib_flush(); rt_cache_flush(0); arp_ifdown(dev); } static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr) { struct in_ifaddr *ifa = (struct in_ifaddr*)ptr; switch (event) { case NETDEV_UP: fib_add_ifaddr(ifa); #ifdef CONFIG_IP_ROUTE_MULTIPATH fib_sync_up(ifa->ifa_dev->dev); #endif rt_cache_flush(-1); break; case NETDEV_DOWN: fib_del_ifaddr(ifa); if (ifa->ifa_dev->ifa_list == NULL) { /* Last address was deleted from this interface. Disable IP. */ fib_disable_ip(ifa->ifa_dev->dev, 1); } else { rt_cache_flush(-1); } break; } return NOTIFY_DONE; } static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) { struct net_device *dev = ptr; struct in_device *in_dev = __in_dev_get_rtnl(dev); if (event == NETDEV_UNREGISTER) { fib_disable_ip(dev, 2); return NOTIFY_DONE; } if (!in_dev) return NOTIFY_DONE; switch (event) { case NETDEV_UP: for_ifa(in_dev) { fib_add_ifaddr(ifa); } endfor_ifa(in_dev); #ifdef CONFIG_IP_ROUTE_MULTIPATH fib_sync_up(dev); #endif rt_cache_flush(-1); break; case NETDEV_DOWN: fib_disable_ip(dev, 0); break; case NETDEV_CHANGEMTU: case NETDEV_CHANGE: rt_cache_flush(0); break; } return NOTIFY_DONE; } static struct notifier_block fib_inetaddr_notifier = { .notifier_call =fib_inetaddr_event, }; static struct notifier_block fib_netdev_notifier = { .notifier_call =fib_netdev_event, }; void __init ip_fib_init(void) { #ifndef CONFIG_IP_MULTIPLE_TABLES ip_fib_local_table = fib_hash_init(RT_TABLE_LOCAL); ip_fib_main_table = fib_hash_init(RT_TABLE_MAIN); #else fib_rules_init(); #endif register_netdevice_notifier(&fib_netdev_notifier); register_inetaddr_notifier(&fib_inetaddr_notifier); nl_fib_lookup_init(); } EXPORT_SYMBOL(inet_addr_type); EXPORT_SYMBOL(ip_rt_ioctl);