// SPDX-License-Identifier: GPL-2.0-or-later /* * 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: policy rules. * * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> * Thomas Graf <tgraf@suug.ch> * * Fixes: * Rani Assaf : local_rule cannot be deleted * Marc Boucher : routing by fwmark */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/netdevice.h> #include <linux/netlink.h> #include <linux/inetdevice.h> #include <linux/init.h> #include <linux/list.h> #include <linux/rcupdate.h> #include <linux/export.h> #include <net/ip.h> #include <net/route.h> #include <net/tcp.h> #include <net/ip_fib.h> #include <net/nexthop.h> #include <net/fib_rules.h> struct fib4_rule { struct fib_rule common; u8 dst_len; u8 src_len; u8 tos; __be32 src; __be32 srcmask; __be32 dst; __be32 dstmask; #ifdef CONFIG_IP_ROUTE_CLASSID u32 tclassid; #endif }; static bool fib4_rule_matchall(const struct fib_rule *rule) { struct fib4_rule *r = container_of(rule, struct fib4_rule, common); if (r->dst_len || r->src_len || r->tos) return false; return fib_rule_matchall(rule); } bool fib4_rule_default(const struct fib_rule *rule) { if (!fib4_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL || rule->l3mdev) return false; if (rule->table != RT_TABLE_LOCAL && rule->table != RT_TABLE_MAIN && rule->table != RT_TABLE_DEFAULT) return false; return true; } EXPORT_SYMBOL_GPL(fib4_rule_default); int fib4_rules_dump(struct net *net, struct notifier_block *nb, struct netlink_ext_ack *extack) { return fib_rules_dump(net, nb, AF_INET, extack); } unsigned int fib4_rules_seq_read(struct net *net) { return fib_rules_seq_read(net, AF_INET); } int __fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res, unsigned int flags) { struct fib_lookup_arg arg = { .result = res, .flags = flags, }; int err; /* update flow if oif or iif point to device enslaved to l3mdev */ l3mdev_update_flow(net, flowi4_to_flowi(flp)); err = fib_rules_lookup(net->ipv4.rules_ops, flowi4_to_flowi(flp), 0, &arg); #ifdef CONFIG_IP_ROUTE_CLASSID if (arg.rule) res->tclassid = ((struct fib4_rule *)arg.rule)->tclassid; else res->tclassid = 0; #endif if (err == -ESRCH) err = -ENETUNREACH; return err; } EXPORT_SYMBOL_GPL(__fib_lookup); static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp, int flags, struct fib_lookup_arg *arg) { int err = -EAGAIN; struct fib_table *tbl; u32 tb_id; switch (rule->action) { case FR_ACT_TO_TBL: break; case FR_ACT_UNREACHABLE: return -ENETUNREACH; case FR_ACT_PROHIBIT: return -EACCES; case FR_ACT_BLACKHOLE: default: return -EINVAL; } rcu_read_lock(); tb_id = fib_rule_get_table(rule, arg); tbl = fib_get_table(rule->fr_net, tb_id); if (tbl) err = fib_table_lookup(tbl, &flp->u.ip4, (struct fib_result *)arg->result, arg->flags); rcu_read_unlock(); return err; } static bool fib4_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) { struct fib_result *result = (struct fib_result *) arg->result; struct net_device *dev = NULL; if (result->fi) { struct fib_nh_common *nhc = fib_info_nhc(result->fi, 0); dev = nhc->nhc_dev; } /* do not accept result if the route does * not meet the required prefix length */ if (result->prefixlen <= rule->suppress_prefixlen) goto suppress_route; /* do not accept result if the route uses a device * belonging to a forbidden interface group */ if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup) goto suppress_route; return false; suppress_route: if (!(arg->flags & FIB_LOOKUP_NOREF)) fib_info_put(result->fi); return true; } static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) { struct fib4_rule *r = (struct fib4_rule *) rule; struct flowi4 *fl4 = &fl->u.ip4; __be32 daddr = fl4->daddr; __be32 saddr = fl4->saddr; if (((saddr ^ r->src) & r->srcmask) || ((daddr ^ r->dst) & r->dstmask)) return 0; if (r->tos && (r->tos != fl4->flowi4_tos)) return 0; if (rule->ip_proto && (rule->ip_proto != fl4->flowi4_proto)) return 0; if (fib_rule_port_range_set(&rule->sport_range) && !fib_rule_port_inrange(&rule->sport_range, fl4->fl4_sport)) return 0; if (fib_rule_port_range_set(&rule->dport_range) && !fib_rule_port_inrange(&rule->dport_range, fl4->fl4_dport)) return 0; return 1; } static struct fib_table *fib_empty_table(struct net *net) { u32 id = 1; while (1) { if (!fib_get_table(net, id)) return fib_new_table(net, id); if (id++ == RT_TABLE_MAX) break; } return NULL; } static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = { FRA_GENERIC_POLICY, [FRA_FLOW] = { .type = NLA_U32 }, }; static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb, struct fib_rule_hdr *frh, struct nlattr **tb, struct netlink_ext_ack *extack) { struct net *net = sock_net(skb->sk); int err = -EINVAL; struct fib4_rule *rule4 = (struct fib4_rule *) rule; if (frh->tos & ~IPTOS_TOS_MASK) { NL_SET_ERR_MSG(extack, "Invalid tos"); goto errout; } /* split local/main if they are not already split */ err = fib_unmerge(net); if (err) goto errout; if (rule->table == RT_TABLE_UNSPEC && !rule->l3mdev) { if (rule->action == FR_ACT_TO_TBL) { struct fib_table *table; table = fib_empty_table(net); if (!table) { err = -ENOBUFS; goto errout; } rule->table = table->tb_id; } } if (frh->src_len) rule4->src = nla_get_in_addr(tb[FRA_SRC]); if (frh->dst_len) rule4->dst = nla_get_in_addr(tb[FRA_DST]); #ifdef CONFIG_IP_ROUTE_CLASSID if (tb[FRA_FLOW]) { rule4->tclassid = nla_get_u32(tb[FRA_FLOW]); if (rule4->tclassid) net->ipv4.fib_num_tclassid_users++; } #endif if (fib_rule_requires_fldissect(rule)) net->ipv4.fib_rules_require_fldissect++; rule4->src_len = frh->src_len; rule4->srcmask = inet_make_mask(rule4->src_len); rule4->dst_len = frh->dst_len; rule4->dstmask = inet_make_mask(rule4->dst_len); rule4->tos = frh->tos; net->ipv4.fib_has_custom_rules = true; err = 0; errout: return err; } static int fib4_rule_delete(struct fib_rule *rule) { struct net *net = rule->fr_net; int err; /* split local/main if they are not already split */ err = fib_unmerge(net); if (err) goto errout; #ifdef CONFIG_IP_ROUTE_CLASSID if (((struct fib4_rule *)rule)->tclassid) net->ipv4.fib_num_tclassid_users--; #endif net->ipv4.fib_has_custom_rules = true; if (net->ipv4.fib_rules_require_fldissect && fib_rule_requires_fldissect(rule)) net->ipv4.fib_rules_require_fldissect--; errout: return err; } static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, struct nlattr **tb) { struct fib4_rule *rule4 = (struct fib4_rule *) rule; if (frh->src_len && (rule4->src_len != frh->src_len)) return 0; if (frh->dst_len && (rule4->dst_len != frh->dst_len)) return 0; if (frh->tos && (rule4->tos != frh->tos)) return 0; #ifdef CONFIG_IP_ROUTE_CLASSID if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW]))) return 0; #endif if (frh->src_len && (rule4->src != nla_get_in_addr(tb[FRA_SRC]))) return 0; if (frh->dst_len && (rule4->dst != nla_get_in_addr(tb[FRA_DST]))) return 0; return 1; } static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb, struct fib_rule_hdr *frh) { struct fib4_rule *rule4 = (struct fib4_rule *) rule; frh->dst_len = rule4->dst_len; frh->src_len = rule4->src_len; frh->tos = rule4->tos; if ((rule4->dst_len && nla_put_in_addr(skb, FRA_DST, rule4->dst)) || (rule4->src_len && nla_put_in_addr(skb, FRA_SRC, rule4->src))) goto nla_put_failure; #ifdef CONFIG_IP_ROUTE_CLASSID if (rule4->tclassid && nla_put_u32(skb, FRA_FLOW, rule4->tclassid)) goto nla_put_failure; #endif return 0; nla_put_failure: return -ENOBUFS; } static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule) { return nla_total_size(4) /* dst */ + nla_total_size(4) /* src */ + nla_total_size(4); /* flow */ } static void fib4_rule_flush_cache(struct fib_rules_ops *ops) { rt_cache_flush(ops->fro_net); } static const struct fib_rules_ops __net_initconst fib4_rules_ops_template = { .family = AF_INET, .rule_size = sizeof(struct fib4_rule), .addr_size = sizeof(u32), .action = fib4_rule_action, .suppress = fib4_rule_suppress, .match = fib4_rule_match, .configure = fib4_rule_configure, .delete = fib4_rule_delete, .compare = fib4_rule_compare, .fill = fib4_rule_fill, .nlmsg_payload = fib4_rule_nlmsg_payload, .flush_cache = fib4_rule_flush_cache, .nlgroup = RTNLGRP_IPV4_RULE, .policy = fib4_rule_policy, .owner = THIS_MODULE, }; static int fib_default_rules_init(struct fib_rules_ops *ops) { int err; err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0); if (err < 0) return err; err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0); if (err < 0) return err; err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0); if (err < 0) return err; return 0; } int __net_init fib4_rules_init(struct net *net) { int err; struct fib_rules_ops *ops; ops = fib_rules_register(&fib4_rules_ops_template, net); if (IS_ERR(ops)) return PTR_ERR(ops); err = fib_default_rules_init(ops); if (err < 0) goto fail; net->ipv4.rules_ops = ops; net->ipv4.fib_has_custom_rules = false; net->ipv4.fib_rules_require_fldissect = 0; return 0; fail: /* also cleans all rules already added */ fib_rules_unregister(ops); return err; } void __net_exit fib4_rules_exit(struct net *net) { fib_rules_unregister(net->ipv4.rules_ops); }