[deliverable/linux.git] / net / bridge / netfilter / nft_reject_bridge.c

/*
 * Copyright (c) 2014 Pablo Neira Ayuso <pablo@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nft_reject.h>
#include <net/netfilter/nf_tables_bridge.h>
#include <net/netfilter/ipv4/nf_reject.h>
#include <net/netfilter/ipv6/nf_reject.h>
#include <linux/ip.h>
#include <net/ip.h>
#include <net/ip6_checksum.h>
#include <linux/netfilter_bridge.h>
#include <linux/netfilter_ipv6.h>
#include "../br_private.h"

static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb,
					struct sk_buff *nskb)
{
	struct ethhdr *eth;

	eth = (struct ethhdr *)skb_push(nskb, ETH_HLEN);
	skb_reset_mac_header(nskb);
	ether_addr_copy(eth->h_source, eth_hdr(oldskb)->h_dest);
	ether_addr_copy(eth->h_dest, eth_hdr(oldskb)->h_source);
	eth->h_proto = eth_hdr(oldskb)->h_proto;
	skb_pull(nskb, ETH_HLEN);
}

/* We cannot use oldskb->dev, it can be either bridge device (NF_BRIDGE INPUT)
 * or the bridge port (NF_BRIDGE PREROUTING).
 */
static void nft_reject_br_send_v4_tcp_reset(struct net *net,
					    struct sk_buff *oldskb,
					    const struct net_device *dev,
					    int hook)
{
	struct sk_buff *nskb;
	struct iphdr *niph;
	const struct tcphdr *oth;
	struct tcphdr _oth;

	if (!nft_bridge_iphdr_validate(oldskb))
		return;

	oth = nf_reject_ip_tcphdr_get(oldskb, &_oth, hook);
	if (!oth)
		return;

	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
			 LL_MAX_HEADER, GFP_ATOMIC);
	if (!nskb)
		return;

	skb_reserve(nskb, LL_MAX_HEADER);
	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_TCP,
				   net->ipv4.sysctl_ip_default_ttl);
	nf_reject_ip_tcphdr_put(nskb, oldskb, oth);
	niph->ttl	= net->ipv4.sysctl_ip_default_ttl;
	niph->tot_len	= htons(nskb->len);
	ip_send_check(niph);

	nft_reject_br_push_etherhdr(oldskb, nskb);

	br_deliver(br_port_get_rcu(dev), nskb);
}

static void nft_reject_br_send_v4_unreach(struct net *net,
					  struct sk_buff *oldskb,
					  const struct net_device *dev,
					  int hook, u8 code)
{
	struct sk_buff *nskb;
	struct iphdr *niph;
	struct icmphdr *icmph;
	unsigned int len;
	void *payload;
	__wsum csum;
	u8 proto;

	if (oldskb->csum_bad || !nft_bridge_iphdr_validate(oldskb))
		return;

	/* IP header checks: fragment. */
	if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
		return;

	/* RFC says return as much as we can without exceeding 576 bytes. */
	len = min_t(unsigned int, 536, oldskb->len);

	if (!pskb_may_pull(oldskb, len))
		return;

	if (pskb_trim_rcsum(oldskb, ntohs(ip_hdr(oldskb)->tot_len)))
		return;

	if (ip_hdr(oldskb)->protocol == IPPROTO_TCP ||
	    ip_hdr(oldskb)->protocol == IPPROTO_UDP)
		proto = ip_hdr(oldskb)->protocol;
	else
		proto = 0;

	if (!skb_csum_unnecessary(oldskb) &&
	    nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), proto))
		return;

	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmphdr) +
			 LL_MAX_HEADER + len, GFP_ATOMIC);
	if (!nskb)
		return;

	skb_reserve(nskb, LL_MAX_HEADER);
	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_ICMP,
				   net->ipv4.sysctl_ip_default_ttl);

	skb_reset_transport_header(nskb);
	icmph = (struct icmphdr *)skb_put(nskb, sizeof(struct icmphdr));
	memset(icmph, 0, sizeof(*icmph));
	icmph->type     = ICMP_DEST_UNREACH;
	icmph->code	= code;

	payload = skb_put(nskb, len);
	memcpy(payload, skb_network_header(oldskb), len);

	csum = csum_partial((void *)icmph, len + sizeof(struct icmphdr), 0);
	icmph->checksum = csum_fold(csum);

	niph->tot_len	= htons(nskb->len);
	ip_send_check(niph);

	nft_reject_br_push_etherhdr(oldskb, nskb);

	br_deliver(br_port_get_rcu(dev), nskb);
}

static void nft_reject_br_send_v6_tcp_reset(struct net *net,
					    struct sk_buff *oldskb,
					    const struct net_device *dev,
					    int hook)
{
	struct sk_buff *nskb;
	const struct tcphdr *oth;
	struct tcphdr _oth;
	unsigned int otcplen;
	struct ipv6hdr *nip6h;

	if (!nft_bridge_ip6hdr_validate(oldskb))
		return;

	oth = nf_reject_ip6_tcphdr_get(oldskb, &_oth, &otcplen, hook);
	if (!oth)
		return;

	nskb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(struct tcphdr) +
			 LL_MAX_HEADER, GFP_ATOMIC);
	if (!nskb)
		return;

	skb_reserve(nskb, LL_MAX_HEADER);
	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP,
				     net->ipv6.devconf_all->hop_limit);
	nf_reject_ip6_tcphdr_put(nskb, oldskb, oth, otcplen);
	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));

	nft_reject_br_push_etherhdr(oldskb, nskb);

	br_deliver(br_port_get_rcu(dev), nskb);
}

static bool reject6_br_csum_ok(struct sk_buff *skb, int hook)
{
	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
	int thoff;
	__be16 fo;
	u8 proto = ip6h->nexthdr;

	if (skb->csum_bad)
		return false;

	if (skb_csum_unnecessary(skb))
		return true;

	if (ip6h->payload_len &&
	    pskb_trim_rcsum(skb, ntohs(ip6h->payload_len) + sizeof(*ip6h)))
		return false;

	thoff = ipv6_skip_exthdr(skb, ((u8*)(ip6h+1) - skb->data), &proto, &fo);
	if (thoff < 0 || thoff >= skb->len || (fo & htons(~0x7)) != 0)
		return false;

	return nf_ip6_checksum(skb, hook, thoff, proto) == 0;
}

static void nft_reject_br_send_v6_unreach(struct net *net,
					  struct sk_buff *oldskb,
					  const struct net_device *dev,
					  int hook, u8 code)
{
	struct sk_buff *nskb;
	struct ipv6hdr *nip6h;
	struct icmp6hdr *icmp6h;
	unsigned int len;
	void *payload;

	if (!nft_bridge_ip6hdr_validate(oldskb))
		return;

	/* Include "As much of invoking packet as possible without the ICMPv6
	 * packet exceeding the minimum IPv6 MTU" in the ICMP payload.
	 */
	len = min_t(unsigned int, 1220, oldskb->len);

	if (!pskb_may_pull(oldskb, len))
		return;

	if (!reject6_br_csum_ok(oldskb, hook))
		return;

	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmp6hdr) +
			 LL_MAX_HEADER + len, GFP_ATOMIC);
	if (!nskb)
		return;

	skb_reserve(nskb, LL_MAX_HEADER);
	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_ICMPV6,
				     net->ipv6.devconf_all->hop_limit);

	skb_reset_transport_header(nskb);
	icmp6h = (struct icmp6hdr *)skb_put(nskb, sizeof(struct icmp6hdr));
	memset(icmp6h, 0, sizeof(*icmp6h));
	icmp6h->icmp6_type = ICMPV6_DEST_UNREACH;
	icmp6h->icmp6_code = code;

	payload = skb_put(nskb, len);
	memcpy(payload, skb_network_header(oldskb), len);
	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));

	icmp6h->icmp6_cksum =
		csum_ipv6_magic(&nip6h->saddr, &nip6h->daddr,
				nskb->len - sizeof(struct ipv6hdr),
				IPPROTO_ICMPV6,
				csum_partial(icmp6h,
					     nskb->len - sizeof(struct ipv6hdr),
					     0));

	nft_reject_br_push_etherhdr(oldskb, nskb);

	br_deliver(br_port_get_rcu(dev), nskb);
}

static void nft_reject_bridge_eval(const struct nft_expr *expr,
				   struct nft_regs *regs,
				   const struct nft_pktinfo *pkt)
{
	struct nft_reject *priv = nft_expr_priv(expr);
	const unsigned char *dest = eth_hdr(pkt->skb)->h_dest;

	if (is_broadcast_ether_addr(dest) ||
	    is_multicast_ether_addr(dest))
		goto out;

	switch (eth_hdr(pkt->skb)->h_proto) {
	case htons(ETH_P_IP):
		switch (priv->type) {
		case NFT_REJECT_ICMP_UNREACH:
			nft_reject_br_send_v4_unreach(pkt->net, pkt->skb,
						      pkt->in, pkt->hook,
						      priv->icmp_code);
			break;
		case NFT_REJECT_TCP_RST:
			nft_reject_br_send_v4_tcp_reset(pkt->net, pkt->skb,
							pkt->in, pkt->hook);
			break;
		case NFT_REJECT_ICMPX_UNREACH:
			nft_reject_br_send_v4_unreach(pkt->net, pkt->skb,
						      pkt->in, pkt->hook,
						      nft_reject_icmp_code(priv->icmp_code));
			break;
		}
		break;
	case htons(ETH_P_IPV6):
		switch (priv->type) {
		case NFT_REJECT_ICMP_UNREACH:
			nft_reject_br_send_v6_unreach(pkt->net, pkt->skb,
						      pkt->in, pkt->hook,
						      priv->icmp_code);
			break;
		case NFT_REJECT_TCP_RST:
			nft_reject_br_send_v6_tcp_reset(pkt->net, pkt->skb,
							pkt->in, pkt->hook);
			break;
		case NFT_REJECT_ICMPX_UNREACH:
			nft_reject_br_send_v6_unreach(pkt->net, pkt->skb,
						      pkt->in, pkt->hook,
						      nft_reject_icmpv6_code(priv->icmp_code));
			break;
		}
		break;
	default:
		/* No explicit way to reject this protocol, drop it. */
		break;
	}
out:
	regs->verdict.code = NF_DROP;
}

static int nft_reject_bridge_validate(const struct nft_ctx *ctx,
				      const struct nft_expr *expr,
				      const struct nft_data **data)
{
	return nft_chain_validate_hooks(ctx->chain, (1 << NF_BR_PRE_ROUTING) |
						    (1 << NF_BR_LOCAL_IN));
}

static int nft_reject_bridge_init(const struct nft_ctx *ctx,
				  const struct nft_expr *expr,
				  const struct nlattr * const tb[])
{
	struct nft_reject *priv = nft_expr_priv(expr);
	int icmp_code, err;

	err = nft_reject_bridge_validate(ctx, expr, NULL);
	if (err < 0)
		return err;

	if (tb[NFTA_REJECT_TYPE] == NULL)
		return -EINVAL;

	priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
	switch (priv->type) {
	case NFT_REJECT_ICMP_UNREACH:
	case NFT_REJECT_ICMPX_UNREACH:
		if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
			return -EINVAL;

		icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
		if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
		    icmp_code > NFT_REJECT_ICMPX_MAX)
			return -EINVAL;

		priv->icmp_code = icmp_code;
		break;
	case NFT_REJECT_TCP_RST:
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

static int nft_reject_bridge_dump(struct sk_buff *skb,
				  const struct nft_expr *expr)
{
	const struct nft_reject *priv = nft_expr_priv(expr);

	if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
		goto nla_put_failure;

	switch (priv->type) {
	case NFT_REJECT_ICMP_UNREACH:
	case NFT_REJECT_ICMPX_UNREACH:
		if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
			goto nla_put_failure;
		break;
	default:
		break;
	}

	return 0;

nla_put_failure:
	return -1;
}

static struct nft_expr_type nft_reject_bridge_type;
static const struct nft_expr_ops nft_reject_bridge_ops = {
	.type		= &nft_reject_bridge_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_reject)),
	.eval		= nft_reject_bridge_eval,
	.init		= nft_reject_bridge_init,
	.dump		= nft_reject_bridge_dump,
	.validate	= nft_reject_bridge_validate,
};

static struct nft_expr_type nft_reject_bridge_type __read_mostly = {
	.family		= NFPROTO_BRIDGE,
	.name		= "reject",
	.ops		= &nft_reject_bridge_ops,
	.policy		= nft_reject_policy,
	.maxattr	= NFTA_REJECT_MAX,
	.owner		= THIS_MODULE,
};

static int __init nft_reject_bridge_module_init(void)
{
	return nft_register_expr(&nft_reject_bridge_type);
}

static void __exit nft_reject_bridge_module_exit(void)
{
	nft_unregister_expr(&nft_reject_bridge_type);
}

module_init(nft_reject_bridge_module_init);
module_exit(nft_reject_bridge_module_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "reject");
Commit	Line	Data
85f5b308 PNA	1	/*
	2	* Copyright (c) 2014 Pablo Neira Ayuso <pablo@netfilter.org>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*/
	8
	9	#include <linux/kernel.h>
	10	#include <linux/init.h>
	11	#include <linux/module.h>
	12	#include <linux/netlink.h>
	13	#include <linux/netfilter.h>
	14	#include <linux/netfilter/nf_tables.h>
	15	#include <net/netfilter/nf_tables.h>
	16	#include <net/netfilter/nft_reject.h>
68b0faa8	17	#include <net/netfilter/nf_tables_bridge.h>
51b0a5d8 PNA	18	#include <net/netfilter/ipv4/nf_reject.h>
51b0a5d8 PNA	19	#include <net/netfilter/ipv6/nf_reject.h>
523b929d PNA	20	#include <linux/ip.h>
523b929d PNA	21	#include <net/ip.h>
c1207c04	22	#include <net/ip6_checksum.h>
127917c2	23	#include <linux/netfilter_bridge.h>
72500bc1	24	#include <linux/netfilter_ipv6.h>
523b929d PNA	25	#include "../br_private.h"
	26
	27	static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb,
	28	struct sk_buff *nskb)
	29	{
	30	struct ethhdr *eth;
	31
	32	eth = (struct ethhdr *)skb_push(nskb, ETH_HLEN);
	33	skb_reset_mac_header(nskb);
	34	ether_addr_copy(eth->h_source, eth_hdr(oldskb)->h_dest);
	35	ether_addr_copy(eth->h_dest, eth_hdr(oldskb)->h_source);
	36	eth->h_proto = eth_hdr(oldskb)->h_proto;
	37	skb_pull(nskb, ETH_HLEN);
	38	}
	39
72500bc1 FW	40	/* We cannot use oldskb->dev, it can be either bridge device (NF_BRIDGE INPUT)
	41	* or the bridge port (NF_BRIDGE PREROUTING).
	42	*/
29421198 LZ	43	static void nft_reject_br_send_v4_tcp_reset(struct net *net,
29421198 LZ	44	struct sk_buff *oldskb,
72500bc1 FW	45	const struct net_device *dev,
72500bc1 FW	46	int hook)
523b929d PNA	47	{
	48	struct sk_buff *nskb;
	49	struct iphdr *niph;
	50	const struct tcphdr *oth;
	51	struct tcphdr _oth;
	52
68b0faa8	53	if (!nft_bridge_iphdr_validate(oldskb))
523b929d PNA	54	return;
	55
	56	oth = nf_reject_ip_tcphdr_get(oldskb, &_oth, hook);
	57	if (!oth)
	58	return;
	59
	60	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
	61	LL_MAX_HEADER, GFP_ATOMIC);
	62	if (!nskb)
	63	return;
	64
	65	skb_reserve(nskb, LL_MAX_HEADER);
	66	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_TCP,
fa50d974	67	net->ipv4.sysctl_ip_default_ttl);
523b929d	68	nf_reject_ip_tcphdr_put(nskb, oldskb, oth);
fa50d974	69	niph->ttl = net->ipv4.sysctl_ip_default_ttl;
523b929d PNA	70	niph->tot_len = htons(nskb->len);
	71	ip_send_check(niph);
	72
	73	nft_reject_br_push_etherhdr(oldskb, nskb);
	74
72500bc1	75	br_deliver(br_port_get_rcu(dev), nskb);
523b929d PNA	76	}
523b929d PNA	77
29421198 LZ	78	static void nft_reject_br_send_v4_unreach(struct net *net,
29421198 LZ	79	struct sk_buff *oldskb,
72500bc1 FW	80	const struct net_device *dev,
72500bc1 FW	81	int hook, u8 code)
523b929d PNA	82	{
	83	struct sk_buff *nskb;
	84	struct iphdr *niph;
	85	struct icmphdr *icmph;
	86	unsigned int len;
	87	void *payload;
	88	__wsum csum;
72500bc1	89	u8 proto;
523b929d	90
72500bc1	91	if (oldskb->csum_bad \|\| !nft_bridge_iphdr_validate(oldskb))
523b929d PNA	92	return;
	93
	94	/* IP header checks: fragment. */
	95	if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
	96	return;
	97
	98	/* RFC says return as much as we can without exceeding 576 bytes. */
	99	len = min_t(unsigned int, 536, oldskb->len);
	100
	101	if (!pskb_may_pull(oldskb, len))
	102	return;
	103
a03a8dbe	104	if (pskb_trim_rcsum(oldskb, ntohs(ip_hdr(oldskb)->tot_len)))
72500bc1 FW	105	return;
	106
	107	if (ip_hdr(oldskb)->protocol == IPPROTO_TCP \|\|
	108	ip_hdr(oldskb)->protocol == IPPROTO_UDP)
	109	proto = ip_hdr(oldskb)->protocol;
	110	else
	111	proto = 0;
	112
	113	if (!skb_csum_unnecessary(oldskb) &&
	114	nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), proto))
523b929d PNA	115	return;
	116
	117	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmphdr) +
	118	LL_MAX_HEADER + len, GFP_ATOMIC);
	119	if (!nskb)
	120	return;
	121
	122	skb_reserve(nskb, LL_MAX_HEADER);
	123	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_ICMP,
fa50d974	124	net->ipv4.sysctl_ip_default_ttl);
523b929d PNA	125
	126	skb_reset_transport_header(nskb);
	127	icmph = (struct icmphdr *)skb_put(nskb, sizeof(struct icmphdr));
	128	memset(icmph, 0, sizeof(*icmph));
	129	icmph->type = ICMP_DEST_UNREACH;
	130	icmph->code = code;
	131
	132	payload = skb_put(nskb, len);
	133	memcpy(payload, skb_network_header(oldskb), len);
	134
	135	csum = csum_partial((void *)icmph, len + sizeof(struct icmphdr), 0);
	136	icmph->checksum = csum_fold(csum);
	137
	138	niph->tot_len = htons(nskb->len);
	139	ip_send_check(niph);
	140
	141	nft_reject_br_push_etherhdr(oldskb, nskb);
	142
72500bc1	143	br_deliver(br_port_get_rcu(dev), nskb);
523b929d PNA	144	}
523b929d PNA	145
523b929d	146	static void nft_reject_br_send_v6_tcp_reset(struct net *net,
72500bc1 FW	147	struct sk_buff *oldskb,
	148	const struct net_device *dev,
	149	int hook)
523b929d PNA	150	{
	151	struct sk_buff *nskb;
	152	const struct tcphdr *oth;
	153	struct tcphdr _oth;
	154	unsigned int otcplen;
	155	struct ipv6hdr *nip6h;
	156
68b0faa8	157	if (!nft_bridge_ip6hdr_validate(oldskb))
523b929d PNA	158	return;
	159
	160	oth = nf_reject_ip6_tcphdr_get(oldskb, &_oth, &otcplen, hook);
	161	if (!oth)
	162	return;
	163
	164	nskb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(struct tcphdr) +
	165	LL_MAX_HEADER, GFP_ATOMIC);
	166	if (!nskb)
	167	return;
	168
	169	skb_reserve(nskb, LL_MAX_HEADER);
	170	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP,
	171	net->ipv6.devconf_all->hop_limit);
	172	nf_reject_ip6_tcphdr_put(nskb, oldskb, oth, otcplen);
	173	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
	174
	175	nft_reject_br_push_etherhdr(oldskb, nskb);
	176
72500bc1 FW	177	br_deliver(br_port_get_rcu(dev), nskb);
	178	}
	179
	180	static bool reject6_br_csum_ok(struct sk_buff *skb, int hook)
	181	{
	182	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
	183	int thoff;
	184	__be16 fo;
	185	u8 proto = ip6h->nexthdr;
	186
	187	if (skb->csum_bad)
	188	return false;
	189
	190	if (skb_csum_unnecessary(skb))
	191	return true;
	192
	193	if (ip6h->payload_len &&
	194	pskb_trim_rcsum(skb, ntohs(ip6h->payload_len) + sizeof(*ip6h)))
	195	return false;
	196
	197	thoff = ipv6_skip_exthdr(skb, ((u8*)(ip6h+1) - skb->data), &proto, &fo);
	198	if (thoff < 0 \|\| thoff >= skb->len \|\| (fo & htons(~0x7)) != 0)
	199	return false;
	200
	201	return nf_ip6_checksum(skb, hook, thoff, proto) == 0;
523b929d PNA	202	}
	203
	204	static void nft_reject_br_send_v6_unreach(struct net *net,
72500bc1 FW	205	struct sk_buff *oldskb,
	206	const struct net_device *dev,
	207	int hook, u8 code)
523b929d PNA	208	{
	209	struct sk_buff *nskb;
	210	struct ipv6hdr *nip6h;
	211	struct icmp6hdr *icmp6h;
	212	unsigned int len;
	213	void *payload;
	214
68b0faa8	215	if (!nft_bridge_ip6hdr_validate(oldskb))
523b929d PNA	216	return;
	217
	218	/* Include "As much of invoking packet as possible without the ICMPv6
	219	* packet exceeding the minimum IPv6 MTU" in the ICMP payload.
	220	*/
	221	len = min_t(unsigned int, 1220, oldskb->len);
	222
	223	if (!pskb_may_pull(oldskb, len))
	224	return;
	225
72500bc1 FW	226	if (!reject6_br_csum_ok(oldskb, hook))
	227	return;
	228
523b929d PNA	229	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmp6hdr) +
	230	LL_MAX_HEADER + len, GFP_ATOMIC);
	231	if (!nskb)
	232	return;
	233
	234	skb_reserve(nskb, LL_MAX_HEADER);
	235	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_ICMPV6,
	236	net->ipv6.devconf_all->hop_limit);
	237
	238	skb_reset_transport_header(nskb);
	239	icmp6h = (struct icmp6hdr *)skb_put(nskb, sizeof(struct icmp6hdr));
	240	memset(icmp6h, 0, sizeof(*icmp6h));
	241	icmp6h->icmp6_type = ICMPV6_DEST_UNREACH;
	242	icmp6h->icmp6_code = code;
	243
	244	payload = skb_put(nskb, len);
	245	memcpy(payload, skb_network_header(oldskb), len);
	246	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
	247
	248	icmp6h->icmp6_cksum =
	249	csum_ipv6_magic(&nip6h->saddr, &nip6h->daddr,
	250	nskb->len - sizeof(struct ipv6hdr),
	251	IPPROTO_ICMPV6,
	252	csum_partial(icmp6h,
	253	nskb->len - sizeof(struct ipv6hdr),
	254	0));
	255
	256	nft_reject_br_push_etherhdr(oldskb, nskb);
	257
72500bc1	258	br_deliver(br_port_get_rcu(dev), nskb);
523b929d	259	}
85f5b308 PNA	260
85f5b308 PNA	261	static void nft_reject_bridge_eval(const struct nft_expr *expr,
a55e22e9 PM	262	struct nft_regs *regs,
a55e22e9 PM	263	const struct nft_pktinfo *pkt)
85f5b308	264	{
51b0a5d8	265	struct nft_reject *priv = nft_expr_priv(expr);
523b929d PNA	266	const unsigned char *dest = eth_hdr(pkt->skb)->h_dest;
	267
	268	if (is_broadcast_ether_addr(dest) \|\|
	269	is_multicast_ether_addr(dest))
	270	goto out;
51b0a5d8	271
85f5b308 PNA	272	switch (eth_hdr(pkt->skb)->h_proto) {
85f5b308 PNA	273	case htons(ETH_P_IP):
51b0a5d8 PNA	274	switch (priv->type) {
51b0a5d8 PNA	275	case NFT_REJECT_ICMP_UNREACH:
29421198 LZ	276	nft_reject_br_send_v4_unreach(pkt->net, pkt->skb,
29421198 LZ	277	pkt->in, pkt->hook,
523b929d	278	priv->icmp_code);
51b0a5d8 PNA	279	break;
51b0a5d8 PNA	280	case NFT_REJECT_TCP_RST:
29421198 LZ	281	nft_reject_br_send_v4_tcp_reset(pkt->net, pkt->skb,
29421198 LZ	282	pkt->in, pkt->hook);
51b0a5d8 PNA	283	break;
51b0a5d8 PNA	284	case NFT_REJECT_ICMPX_UNREACH:
29421198 LZ	285	nft_reject_br_send_v4_unreach(pkt->net, pkt->skb,
29421198 LZ	286	pkt->in, pkt->hook,
523b929d	287	nft_reject_icmp_code(priv->icmp_code));
51b0a5d8 PNA	288	break;
	289	}
	290	break;
85f5b308	291	case htons(ETH_P_IPV6):
51b0a5d8 PNA	292	switch (priv->type) {
51b0a5d8 PNA	293	case NFT_REJECT_ICMP_UNREACH:
88182a0e EB	294	nft_reject_br_send_v6_unreach(pkt->net, pkt->skb,
88182a0e EB	295	pkt->in, pkt->hook,
523b929d	296	priv->icmp_code);
51b0a5d8 PNA	297	break;
51b0a5d8 PNA	298	case NFT_REJECT_TCP_RST:
88182a0e EB	299	nft_reject_br_send_v6_tcp_reset(pkt->net, pkt->skb,
88182a0e EB	300	pkt->in, pkt->hook);
51b0a5d8 PNA	301	break;
51b0a5d8 PNA	302	case NFT_REJECT_ICMPX_UNREACH:
88182a0e EB	303	nft_reject_br_send_v6_unreach(pkt->net, pkt->skb,
88182a0e EB	304	pkt->in, pkt->hook,
523b929d	305	nft_reject_icmpv6_code(priv->icmp_code));
51b0a5d8 PNA	306	break;
	307	}
	308	break;
85f5b308 PNA	309	default:
85f5b308 PNA	310	/* No explicit way to reject this protocol, drop it. */
85f5b308 PNA	311	break;
85f5b308 PNA	312	}
523b929d	313	out:
a55e22e9	314	regs->verdict.code = NF_DROP;
51b0a5d8 PNA	315	}
51b0a5d8 PNA	316
75e8d06d PNA	317	static int nft_reject_bridge_validate(const struct nft_ctx *ctx,
	318	const struct nft_expr *expr,
	319	const struct nft_data **data)
127917c2	320	{
75e8d06d PNA	321	return nft_chain_validate_hooks(ctx->chain, (1 << NF_BR_PRE_ROUTING) \|
75e8d06d PNA	322	(1 << NF_BR_LOCAL_IN));
127917c2 PNA	323	}
127917c2 PNA	324
51b0a5d8 PNA	325	static int nft_reject_bridge_init(const struct nft_ctx *ctx,
	326	const struct nft_expr *expr,
	327	const struct nlattr * const tb[])
	328	{
	329	struct nft_reject *priv = nft_expr_priv(expr);
127917c2 PNA	330	int icmp_code, err;
127917c2 PNA	331
75e8d06d	332	err = nft_reject_bridge_validate(ctx, expr, NULL);
127917c2 PNA	333	if (err < 0)
127917c2 PNA	334	return err;
51b0a5d8 PNA	335
	336	if (tb[NFTA_REJECT_TYPE] == NULL)
	337	return -EINVAL;
	338
	339	priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
	340	switch (priv->type) {
	341	case NFT_REJECT_ICMP_UNREACH:
	342	case NFT_REJECT_ICMPX_UNREACH:
	343	if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
	344	return -EINVAL;
	345
	346	icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
	347	if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
	348	icmp_code > NFT_REJECT_ICMPX_MAX)
	349	return -EINVAL;
	350
	351	priv->icmp_code = icmp_code;
	352	break;
	353	case NFT_REJECT_TCP_RST:
	354	break;
	355	default:
	356	return -EINVAL;
	357	}
	358	return 0;
	359	}
	360
	361	static int nft_reject_bridge_dump(struct sk_buff *skb,
	362	const struct nft_expr *expr)
	363	{
	364	const struct nft_reject *priv = nft_expr_priv(expr);
	365
	366	if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
	367	goto nla_put_failure;
	368
	369	switch (priv->type) {
	370	case NFT_REJECT_ICMP_UNREACH:
	371	case NFT_REJECT_ICMPX_UNREACH:
	372	if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
	373	goto nla_put_failure;
	374	break;
c1f86676 DM	375	default:
c1f86676 DM	376	break;
51b0a5d8 PNA	377	}
	378
	379	return 0;
	380
	381	nla_put_failure:
	382	return -1;
85f5b308 PNA	383	}
	384
	385	static struct nft_expr_type nft_reject_bridge_type;
	386	static const struct nft_expr_ops nft_reject_bridge_ops = {
	387	.type = &nft_reject_bridge_type,
	388	.size = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
	389	.eval = nft_reject_bridge_eval,
51b0a5d8 PNA	390	.init = nft_reject_bridge_init,
51b0a5d8 PNA	391	.dump = nft_reject_bridge_dump,
127917c2	392	.validate = nft_reject_bridge_validate,
85f5b308 PNA	393	};
	394
	395	static struct nft_expr_type nft_reject_bridge_type __read_mostly = {
	396	.family = NFPROTO_BRIDGE,
	397	.name = "reject",
	398	.ops = &nft_reject_bridge_ops,
	399	.policy = nft_reject_policy,
	400	.maxattr = NFTA_REJECT_MAX,
	401	.owner = THIS_MODULE,
	402	};
	403
	404	static int __init nft_reject_bridge_module_init(void)
	405	{
	406	return nft_register_expr(&nft_reject_bridge_type);
	407	}
	408
	409	static void __exit nft_reject_bridge_module_exit(void)
	410	{
	411	nft_unregister_expr(&nft_reject_bridge_type);
	412	}
	413
	414	module_init(nft_reject_bridge_module_init);
	415	module_exit(nft_reject_bridge_module_exit);
	416
	417	MODULE_LICENSE("GPL");
	418	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
	419	MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "reject");