| /* |
| * net/sched/em_ipt.c IPtables matches Ematch |
| * |
| * (c) 2018 Eyal Birger <eyal.birger@gmail.com> |
| * |
| * 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/gfp.h> |
| #include <linux/module.h> |
| #include <linux/types.h> |
| #include <linux/kernel.h> |
| #include <linux/string.h> |
| #include <linux/skbuff.h> |
| #include <linux/tc_ematch/tc_em_ipt.h> |
| #include <linux/netfilter.h> |
| #include <linux/netfilter/x_tables.h> |
| #include <linux/netfilter_ipv4/ip_tables.h> |
| #include <linux/netfilter_ipv6/ip6_tables.h> |
| #include <net/pkt_cls.h> |
| |
| struct em_ipt_match { |
| const struct xt_match *match; |
| u32 hook; |
| u8 match_data[0] __aligned(8); |
| }; |
| |
| struct em_ipt_xt_match { |
| char *match_name; |
| int (*validate_match_data)(struct nlattr **tb, u8 mrev); |
| }; |
| |
| static const struct nla_policy em_ipt_policy[TCA_EM_IPT_MAX + 1] = { |
| [TCA_EM_IPT_MATCH_NAME] = { .type = NLA_STRING, |
| .len = XT_EXTENSION_MAXNAMELEN }, |
| [TCA_EM_IPT_MATCH_REVISION] = { .type = NLA_U8 }, |
| [TCA_EM_IPT_HOOK] = { .type = NLA_U32 }, |
| [TCA_EM_IPT_NFPROTO] = { .type = NLA_U8 }, |
| [TCA_EM_IPT_MATCH_DATA] = { .type = NLA_UNSPEC }, |
| }; |
| |
| static int check_match(struct net *net, struct em_ipt_match *im, int mdata_len) |
| { |
| struct xt_mtchk_param mtpar = {}; |
| union { |
| struct ipt_entry e4; |
| struct ip6t_entry e6; |
| } e = {}; |
| |
| mtpar.net = net; |
| mtpar.table = "filter"; |
| mtpar.hook_mask = 1 << im->hook; |
| mtpar.family = im->match->family; |
| mtpar.match = im->match; |
| mtpar.entryinfo = &e; |
| mtpar.matchinfo = (void *)im->match_data; |
| return xt_check_match(&mtpar, mdata_len, 0, 0); |
| } |
| |
| static int policy_validate_match_data(struct nlattr **tb, u8 mrev) |
| { |
| if (mrev != 0) { |
| pr_err("only policy match revision 0 supported"); |
| return -EINVAL; |
| } |
| |
| if (nla_get_u32(tb[TCA_EM_IPT_HOOK]) != NF_INET_PRE_ROUTING) { |
| pr_err("policy can only be matched on NF_INET_PRE_ROUTING"); |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| static const struct em_ipt_xt_match em_ipt_xt_matches[] = { |
| { |
| .match_name = "policy", |
| .validate_match_data = policy_validate_match_data |
| }, |
| {} |
| }; |
| |
| static struct xt_match *get_xt_match(struct nlattr **tb) |
| { |
| const struct em_ipt_xt_match *m; |
| struct nlattr *mname_attr; |
| u8 nfproto, mrev = 0; |
| int ret; |
| |
| mname_attr = tb[TCA_EM_IPT_MATCH_NAME]; |
| for (m = em_ipt_xt_matches; m->match_name; m++) { |
| if (!nla_strcmp(mname_attr, m->match_name)) |
| break; |
| } |
| |
| if (!m->match_name) { |
| pr_err("Unsupported xt match"); |
| return ERR_PTR(-EINVAL); |
| } |
| |
| if (tb[TCA_EM_IPT_MATCH_REVISION]) |
| mrev = nla_get_u8(tb[TCA_EM_IPT_MATCH_REVISION]); |
| |
| ret = m->validate_match_data(tb, mrev); |
| if (ret < 0) |
| return ERR_PTR(ret); |
| |
| nfproto = nla_get_u8(tb[TCA_EM_IPT_NFPROTO]); |
| return xt_request_find_match(nfproto, m->match_name, mrev); |
| } |
| |
| static int em_ipt_change(struct net *net, void *data, int data_len, |
| struct tcf_ematch *em) |
| { |
| struct nlattr *tb[TCA_EM_IPT_MAX + 1]; |
| struct em_ipt_match *im = NULL; |
| struct xt_match *match; |
| int mdata_len, ret; |
| |
| ret = nla_parse_deprecated(tb, TCA_EM_IPT_MAX, data, data_len, |
| em_ipt_policy, NULL); |
| if (ret < 0) |
| return ret; |
| |
| if (!tb[TCA_EM_IPT_HOOK] || !tb[TCA_EM_IPT_MATCH_NAME] || |
| !tb[TCA_EM_IPT_MATCH_DATA] || !tb[TCA_EM_IPT_NFPROTO]) |
| return -EINVAL; |
| |
| match = get_xt_match(tb); |
| if (IS_ERR(match)) { |
| pr_err("unable to load match\n"); |
| return PTR_ERR(match); |
| } |
| |
| mdata_len = XT_ALIGN(nla_len(tb[TCA_EM_IPT_MATCH_DATA])); |
| im = kzalloc(sizeof(*im) + mdata_len, GFP_KERNEL); |
| if (!im) { |
| ret = -ENOMEM; |
| goto err; |
| } |
| |
| im->match = match; |
| im->hook = nla_get_u32(tb[TCA_EM_IPT_HOOK]); |
| nla_memcpy(im->match_data, tb[TCA_EM_IPT_MATCH_DATA], mdata_len); |
| |
| ret = check_match(net, im, mdata_len); |
| if (ret) |
| goto err; |
| |
| em->datalen = sizeof(*im) + mdata_len; |
| em->data = (unsigned long)im; |
| return 0; |
| |
| err: |
| kfree(im); |
| module_put(match->me); |
| return ret; |
| } |
| |
| static void em_ipt_destroy(struct tcf_ematch *em) |
| { |
| struct em_ipt_match *im = (void *)em->data; |
| |
| if (!im) |
| return; |
| |
| if (im->match->destroy) { |
| struct xt_mtdtor_param par = { |
| .net = em->net, |
| .match = im->match, |
| .matchinfo = im->match_data, |
| .family = im->match->family |
| }; |
| im->match->destroy(&par); |
| } |
| module_put(im->match->me); |
| kfree((void *)im); |
| } |
| |
| static int em_ipt_match(struct sk_buff *skb, struct tcf_ematch *em, |
| struct tcf_pkt_info *info) |
| { |
| const struct em_ipt_match *im = (const void *)em->data; |
| struct xt_action_param acpar = {}; |
| struct net_device *indev = NULL; |
| struct nf_hook_state state; |
| int ret; |
| |
| rcu_read_lock(); |
| |
| if (skb->skb_iif) |
| indev = dev_get_by_index_rcu(em->net, skb->skb_iif); |
| |
| nf_hook_state_init(&state, im->hook, im->match->family, |
| indev ?: skb->dev, skb->dev, NULL, em->net, NULL); |
| |
| acpar.match = im->match; |
| acpar.matchinfo = im->match_data; |
| acpar.state = &state; |
| |
| ret = im->match->match(skb, &acpar); |
| |
| rcu_read_unlock(); |
| return ret; |
| } |
| |
| static int em_ipt_dump(struct sk_buff *skb, struct tcf_ematch *em) |
| { |
| struct em_ipt_match *im = (void *)em->data; |
| |
| if (nla_put_string(skb, TCA_EM_IPT_MATCH_NAME, im->match->name) < 0) |
| return -EMSGSIZE; |
| if (nla_put_u32(skb, TCA_EM_IPT_HOOK, im->hook) < 0) |
| return -EMSGSIZE; |
| if (nla_put_u8(skb, TCA_EM_IPT_MATCH_REVISION, im->match->revision) < 0) |
| return -EMSGSIZE; |
| if (nla_put_u8(skb, TCA_EM_IPT_NFPROTO, im->match->family) < 0) |
| return -EMSGSIZE; |
| if (nla_put(skb, TCA_EM_IPT_MATCH_DATA, |
| im->match->usersize ?: im->match->matchsize, |
| im->match_data) < 0) |
| return -EMSGSIZE; |
| |
| return 0; |
| } |
| |
| static struct tcf_ematch_ops em_ipt_ops = { |
| .kind = TCF_EM_IPT, |
| .change = em_ipt_change, |
| .destroy = em_ipt_destroy, |
| .match = em_ipt_match, |
| .dump = em_ipt_dump, |
| .owner = THIS_MODULE, |
| .link = LIST_HEAD_INIT(em_ipt_ops.link) |
| }; |
| |
| static int __init init_em_ipt(void) |
| { |
| return tcf_em_register(&em_ipt_ops); |
| } |
| |
| static void __exit exit_em_ipt(void) |
| { |
| tcf_em_unregister(&em_ipt_ops); |
| } |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Eyal Birger <eyal.birger@gmail.com>"); |
| MODULE_DESCRIPTION("TC extended match for IPtables matches"); |
| |
| module_init(init_em_ipt); |
| module_exit(exit_em_ipt); |
| |
| MODULE_ALIAS_TCF_EMATCH(TCF_EM_IPT); |