[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/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);
}

static int nft_bridge_iphdr_validate(struct sk_buff *skb)
{
	struct iphdr *iph;
	u32 len;

	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
		return 0;

	iph = ip_hdr(skb);
	if (iph->ihl < 5 || iph->version != 4)
		return 0;

	len = ntohs(iph->tot_len);
	if (skb->len < len)
		return 0;
	else if (len < (iph->ihl*4))
		return 0;

	if (!pskb_may_pull(skb, iph->ihl*4))
		return 0;

	return 1;
}

/* 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_forward(br_port_get_rcu(dev), nskb, false, true);
}

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_forward(br_port_get_rcu(dev), nskb, false, true);
}

static int nft_bridge_ip6hdr_validate(struct sk_buff *skb)
{
	struct ipv6hdr *hdr;
	u32 pkt_len;

	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
		return 0;

	hdr = ipv6_hdr(skb);
	if (hdr->version != 6)
		return 0;

	pkt_len = ntohs(hdr->payload_len);
	if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
		return 0;

	return 1;
}

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_forward(br_port_get_rcu(dev), nskb, false, true);
}

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_forward(br_port_get_rcu(dev), nskb, false, true);
}

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>
51b0a5d8 PNA	17	#include <net/netfilter/ipv4/nf_reject.h>
51b0a5d8 PNA	18	#include <net/netfilter/ipv6/nf_reject.h>
523b929d PNA	19	#include <linux/ip.h>
523b929d PNA	20	#include <net/ip.h>
c1207c04	21	#include <net/ip6_checksum.h>
127917c2	22	#include <linux/netfilter_bridge.h>
72500bc1	23	#include <linux/netfilter_ipv6.h>
523b929d PNA	24	#include "../br_private.h"
	25
	26	static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb,
	27	struct sk_buff *nskb)
	28	{
	29	struct ethhdr *eth;
	30
	31	eth = (struct ethhdr *)skb_push(nskb, ETH_HLEN);
	32	skb_reset_mac_header(nskb);
	33	ether_addr_copy(eth->h_source, eth_hdr(oldskb)->h_dest);
	34	ether_addr_copy(eth->h_dest, eth_hdr(oldskb)->h_source);
	35	eth->h_proto = eth_hdr(oldskb)->h_proto;
	36	skb_pull(nskb, ETH_HLEN);
	37	}
	38
10151d7b PNA	39	static int nft_bridge_iphdr_validate(struct sk_buff *skb)
	40	{
	41	struct iphdr *iph;
	42	u32 len;
	43
	44	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
	45	return 0;
	46
	47	iph = ip_hdr(skb);
	48	if (iph->ihl < 5 \|\| iph->version != 4)
	49	return 0;
	50
	51	len = ntohs(iph->tot_len);
	52	if (skb->len < len)
	53	return 0;
	54	else if (len < (iph->ihl*4))
	55	return 0;
	56
	57	if (!pskb_may_pull(skb, iph->ihl*4))
	58	return 0;
	59
	60	return 1;
	61	}
	62
72500bc1 FW	63	/* We cannot use oldskb->dev, it can be either bridge device (NF_BRIDGE INPUT)
	64	* or the bridge port (NF_BRIDGE PREROUTING).
	65	*/
29421198 LZ	66	static void nft_reject_br_send_v4_tcp_reset(struct net *net,
29421198 LZ	67	struct sk_buff *oldskb,
72500bc1 FW	68	const struct net_device *dev,
72500bc1 FW	69	int hook)
523b929d PNA	70	{
	71	struct sk_buff *nskb;
	72	struct iphdr *niph;
	73	const struct tcphdr *oth;
	74	struct tcphdr _oth;
	75
68b0faa8	76	if (!nft_bridge_iphdr_validate(oldskb))
523b929d PNA	77	return;
	78
	79	oth = nf_reject_ip_tcphdr_get(oldskb, &_oth, hook);
	80	if (!oth)
	81	return;
	82
	83	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
	84	LL_MAX_HEADER, GFP_ATOMIC);
	85	if (!nskb)
	86	return;
	87
	88	skb_reserve(nskb, LL_MAX_HEADER);
	89	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_TCP,
fa50d974	90	net->ipv4.sysctl_ip_default_ttl);
523b929d	91	nf_reject_ip_tcphdr_put(nskb, oldskb, oth);
fa50d974	92	niph->ttl = net->ipv4.sysctl_ip_default_ttl;
523b929d PNA	93	niph->tot_len = htons(nskb->len);
	94	ip_send_check(niph);
	95
	96	nft_reject_br_push_etherhdr(oldskb, nskb);
	97
37b090e6	98	br_forward(br_port_get_rcu(dev), nskb, false, true);
523b929d PNA	99	}
523b929d PNA	100
29421198 LZ	101	static void nft_reject_br_send_v4_unreach(struct net *net,
29421198 LZ	102	struct sk_buff *oldskb,
72500bc1 FW	103	const struct net_device *dev,
72500bc1 FW	104	int hook, u8 code)
523b929d PNA	105	{
	106	struct sk_buff *nskb;
	107	struct iphdr *niph;
	108	struct icmphdr *icmph;
	109	unsigned int len;
	110	void *payload;
	111	__wsum csum;
72500bc1	112	u8 proto;
523b929d	113
72500bc1	114	if (oldskb->csum_bad \|\| !nft_bridge_iphdr_validate(oldskb))
523b929d PNA	115	return;
	116
	117	/* IP header checks: fragment. */
	118	if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
	119	return;
	120
	121	/* RFC says return as much as we can without exceeding 576 bytes. */
	122	len = min_t(unsigned int, 536, oldskb->len);
	123
	124	if (!pskb_may_pull(oldskb, len))
	125	return;
	126
a03a8dbe	127	if (pskb_trim_rcsum(oldskb, ntohs(ip_hdr(oldskb)->tot_len)))
72500bc1 FW	128	return;
	129
	130	if (ip_hdr(oldskb)->protocol == IPPROTO_TCP \|\|
	131	ip_hdr(oldskb)->protocol == IPPROTO_UDP)
	132	proto = ip_hdr(oldskb)->protocol;
	133	else
	134	proto = 0;
	135
	136	if (!skb_csum_unnecessary(oldskb) &&
	137	nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), proto))
523b929d PNA	138	return;
	139
	140	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmphdr) +
	141	LL_MAX_HEADER + len, GFP_ATOMIC);
	142	if (!nskb)
	143	return;
	144
	145	skb_reserve(nskb, LL_MAX_HEADER);
	146	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_ICMP,
fa50d974	147	net->ipv4.sysctl_ip_default_ttl);
523b929d PNA	148
	149	skb_reset_transport_header(nskb);
	150	icmph = (struct icmphdr *)skb_put(nskb, sizeof(struct icmphdr));
	151	memset(icmph, 0, sizeof(*icmph));
	152	icmph->type = ICMP_DEST_UNREACH;
	153	icmph->code = code;
	154
	155	payload = skb_put(nskb, len);
	156	memcpy(payload, skb_network_header(oldskb), len);
	157
	158	csum = csum_partial((void *)icmph, len + sizeof(struct icmphdr), 0);
	159	icmph->checksum = csum_fold(csum);
	160
	161	niph->tot_len = htons(nskb->len);
	162	ip_send_check(niph);
	163
	164	nft_reject_br_push_etherhdr(oldskb, nskb);
	165
37b090e6	166	br_forward(br_port_get_rcu(dev), nskb, false, true);
523b929d PNA	167	}
523b929d PNA	168
10151d7b PNA	169	static int nft_bridge_ip6hdr_validate(struct sk_buff *skb)
	170	{
	171	struct ipv6hdr *hdr;
	172	u32 pkt_len;
	173
	174	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
	175	return 0;
	176
	177	hdr = ipv6_hdr(skb);
	178	if (hdr->version != 6)
	179	return 0;
	180
	181	pkt_len = ntohs(hdr->payload_len);
	182	if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
	183	return 0;
	184
	185	return 1;
	186	}
	187
523b929d	188	static void nft_reject_br_send_v6_tcp_reset(struct net *net,
72500bc1 FW	189	struct sk_buff *oldskb,
	190	const struct net_device *dev,
	191	int hook)
523b929d PNA	192	{
	193	struct sk_buff *nskb;
	194	const struct tcphdr *oth;
	195	struct tcphdr _oth;
	196	unsigned int otcplen;
	197	struct ipv6hdr *nip6h;
	198
68b0faa8	199	if (!nft_bridge_ip6hdr_validate(oldskb))
523b929d PNA	200	return;
	201
	202	oth = nf_reject_ip6_tcphdr_get(oldskb, &_oth, &otcplen, hook);
	203	if (!oth)
	204	return;
	205
	206	nskb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(struct tcphdr) +
	207	LL_MAX_HEADER, GFP_ATOMIC);
	208	if (!nskb)
	209	return;
	210
	211	skb_reserve(nskb, LL_MAX_HEADER);
	212	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP,
	213	net->ipv6.devconf_all->hop_limit);
	214	nf_reject_ip6_tcphdr_put(nskb, oldskb, oth, otcplen);
	215	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
	216
	217	nft_reject_br_push_etherhdr(oldskb, nskb);
	218
37b090e6	219	br_forward(br_port_get_rcu(dev), nskb, false, true);
72500bc1 FW	220	}
	221
	222	static bool reject6_br_csum_ok(struct sk_buff *skb, int hook)
	223	{
	224	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
	225	int thoff;
	226	__be16 fo;
	227	u8 proto = ip6h->nexthdr;
	228
	229	if (skb->csum_bad)
	230	return false;
	231
	232	if (skb_csum_unnecessary(skb))
	233	return true;
	234
	235	if (ip6h->payload_len &&
	236	pskb_trim_rcsum(skb, ntohs(ip6h->payload_len) + sizeof(*ip6h)))
	237	return false;
	238
	239	thoff = ipv6_skip_exthdr(skb, ((u8*)(ip6h+1) - skb->data), &proto, &fo);
	240	if (thoff < 0 \|\| thoff >= skb->len \|\| (fo & htons(~0x7)) != 0)
	241	return false;
	242
	243	return nf_ip6_checksum(skb, hook, thoff, proto) == 0;
523b929d PNA	244	}
	245
	246	static void nft_reject_br_send_v6_unreach(struct net *net,
72500bc1 FW	247	struct sk_buff *oldskb,
	248	const struct net_device *dev,
	249	int hook, u8 code)
523b929d PNA	250	{
	251	struct sk_buff *nskb;
	252	struct ipv6hdr *nip6h;
	253	struct icmp6hdr *icmp6h;
	254	unsigned int len;
	255	void *payload;
	256
68b0faa8	257	if (!nft_bridge_ip6hdr_validate(oldskb))
523b929d PNA	258	return;
	259
	260	/* Include "As much of invoking packet as possible without the ICMPv6
	261	* packet exceeding the minimum IPv6 MTU" in the ICMP payload.
	262	*/
	263	len = min_t(unsigned int, 1220, oldskb->len);
	264
	265	if (!pskb_may_pull(oldskb, len))
	266	return;
	267
72500bc1 FW	268	if (!reject6_br_csum_ok(oldskb, hook))
	269	return;
	270
523b929d PNA	271	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmp6hdr) +
	272	LL_MAX_HEADER + len, GFP_ATOMIC);
	273	if (!nskb)
	274	return;
	275
	276	skb_reserve(nskb, LL_MAX_HEADER);
	277	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_ICMPV6,
	278	net->ipv6.devconf_all->hop_limit);
	279
	280	skb_reset_transport_header(nskb);
	281	icmp6h = (struct icmp6hdr *)skb_put(nskb, sizeof(struct icmp6hdr));
	282	memset(icmp6h, 0, sizeof(*icmp6h));
	283	icmp6h->icmp6_type = ICMPV6_DEST_UNREACH;
	284	icmp6h->icmp6_code = code;
	285
	286	payload = skb_put(nskb, len);
	287	memcpy(payload, skb_network_header(oldskb), len);
	288	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
	289
	290	icmp6h->icmp6_cksum =
	291	csum_ipv6_magic(&nip6h->saddr, &nip6h->daddr,
	292	nskb->len - sizeof(struct ipv6hdr),
	293	IPPROTO_ICMPV6,
	294	csum_partial(icmp6h,
	295	nskb->len - sizeof(struct ipv6hdr),
	296	0));
	297
	298	nft_reject_br_push_etherhdr(oldskb, nskb);
	299
37b090e6	300	br_forward(br_port_get_rcu(dev), nskb, false, true);
523b929d	301	}
85f5b308 PNA	302
85f5b308 PNA	303	static void nft_reject_bridge_eval(const struct nft_expr *expr,
a55e22e9 PM	304	struct nft_regs *regs,
a55e22e9 PM	305	const struct nft_pktinfo *pkt)
85f5b308	306	{
51b0a5d8	307	struct nft_reject *priv = nft_expr_priv(expr);
523b929d PNA	308	const unsigned char *dest = eth_hdr(pkt->skb)->h_dest;
	309
	310	if (is_broadcast_ether_addr(dest) \|\|
	311	is_multicast_ether_addr(dest))
	312	goto out;
51b0a5d8	313
85f5b308 PNA	314	switch (eth_hdr(pkt->skb)->h_proto) {
85f5b308 PNA	315	case htons(ETH_P_IP):
51b0a5d8 PNA	316	switch (priv->type) {
51b0a5d8 PNA	317	case NFT_REJECT_ICMP_UNREACH:
29421198 LZ	318	nft_reject_br_send_v4_unreach(pkt->net, pkt->skb,
29421198 LZ	319	pkt->in, pkt->hook,
523b929d	320	priv->icmp_code);
51b0a5d8 PNA	321	break;
51b0a5d8 PNA	322	case NFT_REJECT_TCP_RST:
29421198 LZ	323	nft_reject_br_send_v4_tcp_reset(pkt->net, pkt->skb,
29421198 LZ	324	pkt->in, pkt->hook);
51b0a5d8 PNA	325	break;
51b0a5d8 PNA	326	case NFT_REJECT_ICMPX_UNREACH:
29421198 LZ	327	nft_reject_br_send_v4_unreach(pkt->net, pkt->skb,
29421198 LZ	328	pkt->in, pkt->hook,
523b929d	329	nft_reject_icmp_code(priv->icmp_code));
51b0a5d8 PNA	330	break;
	331	}
	332	break;
85f5b308	333	case htons(ETH_P_IPV6):
51b0a5d8 PNA	334	switch (priv->type) {
51b0a5d8 PNA	335	case NFT_REJECT_ICMP_UNREACH:
88182a0e EB	336	nft_reject_br_send_v6_unreach(pkt->net, pkt->skb,
88182a0e EB	337	pkt->in, pkt->hook,
523b929d	338	priv->icmp_code);
51b0a5d8 PNA	339	break;
51b0a5d8 PNA	340	case NFT_REJECT_TCP_RST:
88182a0e EB	341	nft_reject_br_send_v6_tcp_reset(pkt->net, pkt->skb,
88182a0e EB	342	pkt->in, pkt->hook);
51b0a5d8 PNA	343	break;
51b0a5d8 PNA	344	case NFT_REJECT_ICMPX_UNREACH:
88182a0e EB	345	nft_reject_br_send_v6_unreach(pkt->net, pkt->skb,
88182a0e EB	346	pkt->in, pkt->hook,
523b929d	347	nft_reject_icmpv6_code(priv->icmp_code));
51b0a5d8 PNA	348	break;
	349	}
	350	break;
85f5b308 PNA	351	default:
85f5b308 PNA	352	/* No explicit way to reject this protocol, drop it. */
85f5b308 PNA	353	break;
85f5b308 PNA	354	}
523b929d	355	out:
a55e22e9	356	regs->verdict.code = NF_DROP;
51b0a5d8 PNA	357	}
51b0a5d8 PNA	358
75e8d06d PNA	359	static int nft_reject_bridge_validate(const struct nft_ctx *ctx,
	360	const struct nft_expr *expr,
	361	const struct nft_data **data)
127917c2	362	{
75e8d06d PNA	363	return nft_chain_validate_hooks(ctx->chain, (1 << NF_BR_PRE_ROUTING) \|
75e8d06d PNA	364	(1 << NF_BR_LOCAL_IN));
127917c2 PNA	365	}
127917c2 PNA	366
51b0a5d8 PNA	367	static int nft_reject_bridge_init(const struct nft_ctx *ctx,
	368	const struct nft_expr *expr,
	369	const struct nlattr * const tb[])
	370	{
	371	struct nft_reject *priv = nft_expr_priv(expr);
127917c2 PNA	372	int icmp_code, err;
127917c2 PNA	373
75e8d06d	374	err = nft_reject_bridge_validate(ctx, expr, NULL);
127917c2 PNA	375	if (err < 0)
127917c2 PNA	376	return err;
51b0a5d8 PNA	377
	378	if (tb[NFTA_REJECT_TYPE] == NULL)
	379	return -EINVAL;
	380
	381	priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
	382	switch (priv->type) {
	383	case NFT_REJECT_ICMP_UNREACH:
	384	case NFT_REJECT_ICMPX_UNREACH:
	385	if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
	386	return -EINVAL;
	387
	388	icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
	389	if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
	390	icmp_code > NFT_REJECT_ICMPX_MAX)
	391	return -EINVAL;
	392
	393	priv->icmp_code = icmp_code;
	394	break;
	395	case NFT_REJECT_TCP_RST:
	396	break;
	397	default:
	398	return -EINVAL;
	399	}
	400	return 0;
	401	}
	402
	403	static int nft_reject_bridge_dump(struct sk_buff *skb,
	404	const struct nft_expr *expr)
	405	{
	406	const struct nft_reject *priv = nft_expr_priv(expr);
	407
	408	if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
	409	goto nla_put_failure;
	410
	411	switch (priv->type) {
	412	case NFT_REJECT_ICMP_UNREACH:
	413	case NFT_REJECT_ICMPX_UNREACH:
	414	if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
	415	goto nla_put_failure;
	416	break;
c1f86676 DM	417	default:
c1f86676 DM	418	break;
51b0a5d8 PNA	419	}
	420
	421	return 0;
	422
	423	nla_put_failure:
	424	return -1;
85f5b308 PNA	425	}
	426
	427	static struct nft_expr_type nft_reject_bridge_type;
	428	static const struct nft_expr_ops nft_reject_bridge_ops = {
	429	.type = &nft_reject_bridge_type,
	430	.size = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
	431	.eval = nft_reject_bridge_eval,
51b0a5d8 PNA	432	.init = nft_reject_bridge_init,
51b0a5d8 PNA	433	.dump = nft_reject_bridge_dump,
127917c2	434	.validate = nft_reject_bridge_validate,
85f5b308 PNA	435	};
	436
	437	static struct nft_expr_type nft_reject_bridge_type __read_mostly = {
	438	.family = NFPROTO_BRIDGE,
	439	.name = "reject",
	440	.ops = &nft_reject_bridge_ops,
	441	.policy = nft_reject_policy,
	442	.maxattr = NFTA_REJECT_MAX,
	443	.owner = THIS_MODULE,
	444	};
	445
	446	static int __init nft_reject_bridge_module_init(void)
	447	{
	448	return nft_register_expr(&nft_reject_bridge_type);
	449	}
	450
	451	static void __exit nft_reject_bridge_module_exit(void)
	452	{
	453	nft_unregister_expr(&nft_reject_bridge_type);
	454	}
	455
	456	module_init(nft_reject_bridge_module_init);
	457	module_exit(nft_reject_bridge_module_exit);
	458
	459	MODULE_LICENSE("GPL");
	460	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
	461	MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "reject");