| /* |
| * 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> |
| * |
| * 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. |
| * |
| * 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/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 |
| }; |
| |
| 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) |
| dev = result->fi->fib_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; |
| |
| return 1; |
| } |
| |
| static struct fib_table *fib_empty_table(struct net *net) |
| { |
| u32 id; |
| |
| for (id = 1; id <= RT_TABLE_MAX; id++) |
| if (!fib_get_table(net, id)) |
| return fib_new_table(net, id); |
| 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 net *net = sock_net(skb->sk); |
| int err = -EINVAL; |
| struct fib4_rule *rule4 = (struct fib4_rule *) rule; |
| |
| if (frh->tos & ~IPTOS_TOS_MASK) |
| 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 |
| |
| 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; |
| fib_flush_external(rule->fr_net); |
| |
| 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; |
| fib_flush_external(rule->fr_net); |
| 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; |
| 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); |
| } |