330 lines
7.0 KiB
C
330 lines
7.0 KiB
C
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/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* IPv4 Forwarding Information Base: policy rules.
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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* Thomas Graf <tgraf@suug.ch>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Fixes:
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* Rani Assaf : local_rule cannot be deleted
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* Marc Boucher : routing by fwmark
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/netlink.h>
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#include <linux/inetdevice.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/rcupdate.h>
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#include <net/ip.h>
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#include <net/route.h>
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#include <net/tcp.h>
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#include <net/ip_fib.h>
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#include <net/fib_rules.h>
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struct fib4_rule
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{
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struct fib_rule common;
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u8 dst_len;
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u8 src_len;
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u8 tos;
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__be32 src;
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__be32 srcmask;
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__be32 dst;
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__be32 dstmask;
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#ifdef CONFIG_NET_CLS_ROUTE
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u32 tclassid;
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#endif
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};
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#ifdef CONFIG_NET_CLS_ROUTE
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u32 fib_rules_tclass(struct fib_result *res)
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{
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return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0;
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}
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#endif
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int fib_lookup(struct net *net, struct flowi *flp, struct fib_result *res)
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{
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struct fib_lookup_arg arg = {
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.result = res,
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};
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int err;
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err = fib_rules_lookup(net->ipv4.rules_ops, flp, 0, &arg);
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res->r = arg.rule;
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return err;
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}
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static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,
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int flags, struct fib_lookup_arg *arg)
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{
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int err = -EAGAIN;
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struct fib_table *tbl;
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switch (rule->action) {
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case FR_ACT_TO_TBL:
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break;
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case FR_ACT_UNREACHABLE:
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err = -ENETUNREACH;
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goto errout;
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case FR_ACT_PROHIBIT:
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err = -EACCES;
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goto errout;
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case FR_ACT_BLACKHOLE:
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default:
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err = -EINVAL;
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goto errout;
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}
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if ((tbl = fib_get_table(rule->fr_net, rule->table)) == NULL)
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goto errout;
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err = tbl->tb_lookup(tbl, flp, (struct fib_result *) arg->result);
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if (err > 0)
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err = -EAGAIN;
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errout:
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return err;
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}
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static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
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{
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struct fib4_rule *r = (struct fib4_rule *) rule;
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__be32 daddr = fl->fl4_dst;
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__be32 saddr = fl->fl4_src;
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if (((saddr ^ r->src) & r->srcmask) ||
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((daddr ^ r->dst) & r->dstmask))
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return 0;
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if (r->tos && (r->tos != fl->fl4_tos))
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return 0;
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return 1;
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}
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static struct fib_table *fib_empty_table(struct net *net)
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{
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u32 id;
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for (id = 1; id <= RT_TABLE_MAX; id++)
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if (fib_get_table(net, id) == NULL)
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return fib_new_table(net, id);
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return NULL;
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}
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static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {
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FRA_GENERIC_POLICY,
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[FRA_FLOW] = { .type = NLA_U32 },
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};
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static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
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struct fib_rule_hdr *frh,
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struct nlattr **tb)
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{
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struct net *net = sock_net(skb->sk);
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int err = -EINVAL;
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struct fib4_rule *rule4 = (struct fib4_rule *) rule;
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if (frh->tos & ~IPTOS_TOS_MASK)
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goto errout;
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if (rule->table == RT_TABLE_UNSPEC) {
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if (rule->action == FR_ACT_TO_TBL) {
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struct fib_table *table;
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table = fib_empty_table(net);
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if (table == NULL) {
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err = -ENOBUFS;
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goto errout;
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}
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rule->table = table->tb_id;
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}
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}
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if (frh->src_len)
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rule4->src = nla_get_be32(tb[FRA_SRC]);
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if (frh->dst_len)
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rule4->dst = nla_get_be32(tb[FRA_DST]);
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#ifdef CONFIG_NET_CLS_ROUTE
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if (tb[FRA_FLOW])
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rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
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#endif
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rule4->src_len = frh->src_len;
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rule4->srcmask = inet_make_mask(rule4->src_len);
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rule4->dst_len = frh->dst_len;
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rule4->dstmask = inet_make_mask(rule4->dst_len);
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rule4->tos = frh->tos;
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err = 0;
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errout:
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return err;
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}
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static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
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struct nlattr **tb)
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{
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struct fib4_rule *rule4 = (struct fib4_rule *) rule;
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if (frh->src_len && (rule4->src_len != frh->src_len))
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return 0;
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if (frh->dst_len && (rule4->dst_len != frh->dst_len))
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return 0;
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if (frh->tos && (rule4->tos != frh->tos))
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return 0;
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#ifdef CONFIG_NET_CLS_ROUTE
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if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))
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return 0;
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#endif
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if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC])))
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return 0;
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if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST])))
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return 0;
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return 1;
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}
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static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
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struct fib_rule_hdr *frh)
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{
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struct fib4_rule *rule4 = (struct fib4_rule *) rule;
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frh->family = AF_INET;
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frh->dst_len = rule4->dst_len;
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frh->src_len = rule4->src_len;
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frh->tos = rule4->tos;
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if (rule4->dst_len)
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NLA_PUT_BE32(skb, FRA_DST, rule4->dst);
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if (rule4->src_len)
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NLA_PUT_BE32(skb, FRA_SRC, rule4->src);
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#ifdef CONFIG_NET_CLS_ROUTE
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if (rule4->tclassid)
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NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid);
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#endif
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return 0;
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nla_put_failure:
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return -ENOBUFS;
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}
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static u32 fib4_rule_default_pref(struct fib_rules_ops *ops)
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{
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struct list_head *pos;
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struct fib_rule *rule;
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if (!list_empty(&ops->rules_list)) {
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pos = ops->rules_list.next;
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if (pos->next != &ops->rules_list) {
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rule = list_entry(pos->next, struct fib_rule, list);
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if (rule->pref)
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return rule->pref - 1;
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}
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}
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return 0;
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}
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static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)
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{
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return nla_total_size(4) /* dst */
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+ nla_total_size(4) /* src */
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+ nla_total_size(4); /* flow */
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}
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static void fib4_rule_flush_cache(struct fib_rules_ops *ops)
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{
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rt_cache_flush(ops->fro_net, -1);
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}
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static struct fib_rules_ops fib4_rules_ops_template = {
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.family = AF_INET,
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.rule_size = sizeof(struct fib4_rule),
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.addr_size = sizeof(u32),
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.action = fib4_rule_action,
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.match = fib4_rule_match,
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.configure = fib4_rule_configure,
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.compare = fib4_rule_compare,
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.fill = fib4_rule_fill,
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.default_pref = fib4_rule_default_pref,
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.nlmsg_payload = fib4_rule_nlmsg_payload,
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.flush_cache = fib4_rule_flush_cache,
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.nlgroup = RTNLGRP_IPV4_RULE,
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.policy = fib4_rule_policy,
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.owner = THIS_MODULE,
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};
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static int fib_default_rules_init(struct fib_rules_ops *ops)
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{
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int err;
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err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, FIB_RULE_PERMANENT);
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if (err < 0)
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return err;
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err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0);
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if (err < 0)
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return err;
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err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0);
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if (err < 0)
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return err;
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return 0;
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}
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int __net_init fib4_rules_init(struct net *net)
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{
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int err;
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struct fib_rules_ops *ops;
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ops = kmemdup(&fib4_rules_ops_template, sizeof(*ops), GFP_KERNEL);
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if (ops == NULL)
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return -ENOMEM;
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INIT_LIST_HEAD(&ops->rules_list);
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ops->fro_net = net;
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fib_rules_register(ops);
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err = fib_default_rules_init(ops);
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if (err < 0)
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goto fail;
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net->ipv4.rules_ops = ops;
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return 0;
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fail:
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/* also cleans all rules already added */
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fib_rules_unregister(ops);
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kfree(ops);
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return err;
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}
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void __net_exit fib4_rules_exit(struct net *net)
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{
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fib_rules_unregister(net->ipv4.rules_ops);
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kfree(net->ipv4.rules_ops);
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}
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