[mirror_ubuntu-bionic-kernel.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 = 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;
	__wsum csum;
	u8 proto;

	if (!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 = skb_put_zero(nskb, sizeof(struct icmphdr));
	icmph->type     = ICMP_DEST_UNREACH;
	icmph->code	= code;

	skb_put_data(nskb, 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_unnecessary(skb))
		return true;

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

	ip6h = ipv6_hdr(skb);
	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;

	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 = skb_put_zero(nskb, sizeof(struct icmp6hdr));
	icmp6h->icmp6_type = ICMPV6_DEST_UNREACH;
	icmp6h->icmp6_code = code;

	skb_put_data(nskb, 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(nft_net(pkt), pkt->skb,
						      nft_in(pkt),
						      nft_hook(pkt),
						      priv->icmp_code);
			break;
		case NFT_REJECT_TCP_RST:
			nft_reject_br_send_v4_tcp_reset(nft_net(pkt), pkt->skb,
							nft_in(pkt),
							nft_hook(pkt));
			break;
		case NFT_REJECT_ICMPX_UNREACH:
			nft_reject_br_send_v4_unreach(nft_net(pkt), pkt->skb,
						      nft_in(pkt),
						      nft_hook(pkt),
						      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(nft_net(pkt), pkt->skb,
						      nft_in(pkt),
						      nft_hook(pkt),
						      priv->icmp_code);
			break;
		case NFT_REJECT_TCP_RST:
			nft_reject_br_send_v6_tcp_reset(nft_net(pkt), pkt->skb,
							nft_in(pkt),
							nft_hook(pkt));
			break;
		case NFT_REJECT_ICMPX_UNREACH:
			nft_reject_br_send_v6_unreach(nft_net(pkt), pkt->skb,
						      nft_in(pkt),
						      nft_hook(pkt),
						      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;

	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
d58ff351	31	eth = skb_push(nskb, ETH_HLEN);
523b929d PNA	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;
523b929d	110	__wsum csum;
72500bc1	111	u8 proto;
523b929d	112
219f1d79	113	if (!nft_bridge_iphdr_validate(oldskb))
523b929d PNA	114	return;
	115
	116	/* IP header checks: fragment. */
	117	if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
	118	return;
	119
	120	/* RFC says return as much as we can without exceeding 576 bytes. */
	121	len = min_t(unsigned int, 536, oldskb->len);
	122
	123	if (!pskb_may_pull(oldskb, len))
	124	return;
	125
a03a8dbe	126	if (pskb_trim_rcsum(oldskb, ntohs(ip_hdr(oldskb)->tot_len)))
72500bc1 FW	127	return;
	128
	129	if (ip_hdr(oldskb)->protocol == IPPROTO_TCP \|\|
	130	ip_hdr(oldskb)->protocol == IPPROTO_UDP)
	131	proto = ip_hdr(oldskb)->protocol;
	132	else
	133	proto = 0;
	134
	135	if (!skb_csum_unnecessary(oldskb) &&
	136	nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), proto))
523b929d PNA	137	return;
	138
	139	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmphdr) +
	140	LL_MAX_HEADER + len, GFP_ATOMIC);
	141	if (!nskb)
	142	return;
	143
	144	skb_reserve(nskb, LL_MAX_HEADER);
	145	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_ICMP,
fa50d974	146	net->ipv4.sysctl_ip_default_ttl);
523b929d PNA	147
523b929d PNA	148	skb_reset_transport_header(nskb);
b080db58	149	icmph = skb_put_zero(nskb, sizeof(struct icmphdr));
523b929d PNA	150	icmph->type = ICMP_DEST_UNREACH;
	151	icmph->code = code;
	152
b952f4df	153	skb_put_data(nskb, skb_network_header(oldskb), len);
523b929d PNA	154
	155	csum = csum_partial((void *)icmph, len + sizeof(struct icmphdr), 0);
	156	icmph->checksum = csum_fold(csum);
	157
	158	niph->tot_len = htons(nskb->len);
	159	ip_send_check(niph);
	160
	161	nft_reject_br_push_etherhdr(oldskb, nskb);
	162
37b090e6	163	br_forward(br_port_get_rcu(dev), nskb, false, true);
523b929d PNA	164	}
523b929d PNA	165
10151d7b PNA	166	static int nft_bridge_ip6hdr_validate(struct sk_buff *skb)
	167	{
	168	struct ipv6hdr *hdr;
	169	u32 pkt_len;
	170
	171	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
	172	return 0;
	173
	174	hdr = ipv6_hdr(skb);
	175	if (hdr->version != 6)
	176	return 0;
	177
	178	pkt_len = ntohs(hdr->payload_len);
	179	if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
	180	return 0;
	181
	182	return 1;
	183	}
	184
523b929d	185	static void nft_reject_br_send_v6_tcp_reset(struct net *net,
72500bc1 FW	186	struct sk_buff *oldskb,
	187	const struct net_device *dev,
	188	int hook)
523b929d PNA	189	{
	190	struct sk_buff *nskb;
	191	const struct tcphdr *oth;
	192	struct tcphdr _oth;
	193	unsigned int otcplen;
	194	struct ipv6hdr *nip6h;
	195
68b0faa8	196	if (!nft_bridge_ip6hdr_validate(oldskb))
523b929d PNA	197	return;
	198
	199	oth = nf_reject_ip6_tcphdr_get(oldskb, &_oth, &otcplen, hook);
	200	if (!oth)
	201	return;
	202
	203	nskb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(struct tcphdr) +
	204	LL_MAX_HEADER, GFP_ATOMIC);
	205	if (!nskb)
	206	return;
	207
	208	skb_reserve(nskb, LL_MAX_HEADER);
	209	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP,
	210	net->ipv6.devconf_all->hop_limit);
	211	nf_reject_ip6_tcphdr_put(nskb, oldskb, oth, otcplen);
	212	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
	213
	214	nft_reject_br_push_etherhdr(oldskb, nskb);
	215
37b090e6	216	br_forward(br_port_get_rcu(dev), nskb, false, true);
72500bc1 FW	217	}
	218
	219	static bool reject6_br_csum_ok(struct sk_buff *skb, int hook)
	220	{
	221	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
	222	int thoff;
	223	__be16 fo;
	224	u8 proto = ip6h->nexthdr;
	225
72500bc1 FW	226	if (skb_csum_unnecessary(skb))
	227	return true;
	228
	229	if (ip6h->payload_len &&
	230	pskb_trim_rcsum(skb, ntohs(ip6h->payload_len) + sizeof(*ip6h)))
	231	return false;
	232
fc4dee53	233	ip6h = ipv6_hdr(skb);
72500bc1 FW	234	thoff = ipv6_skip_exthdr(skb, ((u8*)(ip6h+1) - skb->data), &proto, &fo);
	235	if (thoff < 0 \|\| thoff >= skb->len \|\| (fo & htons(~0x7)) != 0)
	236	return false;
	237
	238	return nf_ip6_checksum(skb, hook, thoff, proto) == 0;
523b929d PNA	239	}
	240
	241	static void nft_reject_br_send_v6_unreach(struct net *net,
72500bc1 FW	242	struct sk_buff *oldskb,
	243	const struct net_device *dev,
	244	int hook, u8 code)
523b929d PNA	245	{
	246	struct sk_buff *nskb;
	247	struct ipv6hdr *nip6h;
	248	struct icmp6hdr *icmp6h;
	249	unsigned int len;
523b929d	250
68b0faa8	251	if (!nft_bridge_ip6hdr_validate(oldskb))
523b929d PNA	252	return;
	253
	254	/* Include "As much of invoking packet as possible without the ICMPv6
	255	* packet exceeding the minimum IPv6 MTU" in the ICMP payload.
	256	*/
	257	len = min_t(unsigned int, 1220, oldskb->len);
	258
	259	if (!pskb_may_pull(oldskb, len))
	260	return;
	261
72500bc1 FW	262	if (!reject6_br_csum_ok(oldskb, hook))
	263	return;
	264
523b929d PNA	265	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmp6hdr) +
	266	LL_MAX_HEADER + len, GFP_ATOMIC);
	267	if (!nskb)
	268	return;
	269
	270	skb_reserve(nskb, LL_MAX_HEADER);
	271	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_ICMPV6,
	272	net->ipv6.devconf_all->hop_limit);
	273
	274	skb_reset_transport_header(nskb);
b080db58	275	icmp6h = skb_put_zero(nskb, sizeof(struct icmp6hdr));
523b929d PNA	276	icmp6h->icmp6_type = ICMPV6_DEST_UNREACH;
	277	icmp6h->icmp6_code = code;
	278
b952f4df	279	skb_put_data(nskb, skb_network_header(oldskb), len);
523b929d PNA	280	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
	281
	282	icmp6h->icmp6_cksum =
	283	csum_ipv6_magic(&nip6h->saddr, &nip6h->daddr,
	284	nskb->len - sizeof(struct ipv6hdr),
	285	IPPROTO_ICMPV6,
	286	csum_partial(icmp6h,
	287	nskb->len - sizeof(struct ipv6hdr),
	288	0));
	289
	290	nft_reject_br_push_etherhdr(oldskb, nskb);
	291
37b090e6	292	br_forward(br_port_get_rcu(dev), nskb, false, true);
523b929d	293	}
85f5b308 PNA	294
85f5b308 PNA	295	static void nft_reject_bridge_eval(const struct nft_expr *expr,
a55e22e9 PM	296	struct nft_regs *regs,
a55e22e9 PM	297	const struct nft_pktinfo *pkt)
85f5b308	298	{
51b0a5d8	299	struct nft_reject *priv = nft_expr_priv(expr);
523b929d PNA	300	const unsigned char *dest = eth_hdr(pkt->skb)->h_dest;
	301
	302	if (is_broadcast_ether_addr(dest) \|\|
	303	is_multicast_ether_addr(dest))
	304	goto out;
51b0a5d8	305
85f5b308 PNA	306	switch (eth_hdr(pkt->skb)->h_proto) {
85f5b308 PNA	307	case htons(ETH_P_IP):
51b0a5d8 PNA	308	switch (priv->type) {
51b0a5d8 PNA	309	case NFT_REJECT_ICMP_UNREACH:
0e5a1c7e PNA	310	nft_reject_br_send_v4_unreach(nft_net(pkt), pkt->skb,
	311	nft_in(pkt),
	312	nft_hook(pkt),
523b929d	313	priv->icmp_code);
51b0a5d8 PNA	314	break;
51b0a5d8 PNA	315	case NFT_REJECT_TCP_RST:
0e5a1c7e PNA	316	nft_reject_br_send_v4_tcp_reset(nft_net(pkt), pkt->skb,
	317	nft_in(pkt),
	318	nft_hook(pkt));
51b0a5d8 PNA	319	break;
51b0a5d8 PNA	320	case NFT_REJECT_ICMPX_UNREACH:
0e5a1c7e PNA	321	nft_reject_br_send_v4_unreach(nft_net(pkt), pkt->skb,
	322	nft_in(pkt),
	323	nft_hook(pkt),
523b929d	324	nft_reject_icmp_code(priv->icmp_code));
51b0a5d8 PNA	325	break;
	326	}
	327	break;
85f5b308	328	case htons(ETH_P_IPV6):
51b0a5d8 PNA	329	switch (priv->type) {
51b0a5d8 PNA	330	case NFT_REJECT_ICMP_UNREACH:
0e5a1c7e PNA	331	nft_reject_br_send_v6_unreach(nft_net(pkt), pkt->skb,
	332	nft_in(pkt),
	333	nft_hook(pkt),
523b929d	334	priv->icmp_code);
51b0a5d8 PNA	335	break;
51b0a5d8 PNA	336	case NFT_REJECT_TCP_RST:
0e5a1c7e PNA	337	nft_reject_br_send_v6_tcp_reset(nft_net(pkt), pkt->skb,
	338	nft_in(pkt),
	339	nft_hook(pkt));
51b0a5d8 PNA	340	break;
51b0a5d8 PNA	341	case NFT_REJECT_ICMPX_UNREACH:
0e5a1c7e PNA	342	nft_reject_br_send_v6_unreach(nft_net(pkt), pkt->skb,
	343	nft_in(pkt),
	344	nft_hook(pkt),
523b929d	345	nft_reject_icmpv6_code(priv->icmp_code));
51b0a5d8 PNA	346	break;
	347	}
	348	break;
85f5b308 PNA	349	default:
85f5b308 PNA	350	/* No explicit way to reject this protocol, drop it. */
85f5b308 PNA	351	break;
85f5b308 PNA	352	}
523b929d	353	out:
a55e22e9	354	regs->verdict.code = NF_DROP;
51b0a5d8 PNA	355	}
51b0a5d8 PNA	356
75e8d06d PNA	357	static int nft_reject_bridge_validate(const struct nft_ctx *ctx,
	358	const struct nft_expr *expr,
	359	const struct nft_data **data)
127917c2	360	{
75e8d06d PNA	361	return nft_chain_validate_hooks(ctx->chain, (1 << NF_BR_PRE_ROUTING) \|
75e8d06d PNA	362	(1 << NF_BR_LOCAL_IN));
127917c2 PNA	363	}
127917c2 PNA	364
51b0a5d8 PNA	365	static int nft_reject_bridge_init(const struct nft_ctx *ctx,
	366	const struct nft_expr *expr,
	367	const struct nlattr * const tb[])
	368	{
	369	struct nft_reject *priv = nft_expr_priv(expr);
c56e3956	370	int icmp_code;
51b0a5d8 PNA	371
	372	if (tb[NFTA_REJECT_TYPE] == NULL)
	373	return -EINVAL;
	374
	375	priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
	376	switch (priv->type) {
	377	case NFT_REJECT_ICMP_UNREACH:
	378	case NFT_REJECT_ICMPX_UNREACH:
	379	if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
	380	return -EINVAL;
	381
	382	icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
	383	if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
	384	icmp_code > NFT_REJECT_ICMPX_MAX)
	385	return -EINVAL;
	386
	387	priv->icmp_code = icmp_code;
	388	break;
	389	case NFT_REJECT_TCP_RST:
	390	break;
	391	default:
	392	return -EINVAL;
	393	}
	394	return 0;
	395	}
	396
	397	static int nft_reject_bridge_dump(struct sk_buff *skb,
	398	const struct nft_expr *expr)
	399	{
	400	const struct nft_reject *priv = nft_expr_priv(expr);
	401
	402	if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
	403	goto nla_put_failure;
	404
	405	switch (priv->type) {
	406	case NFT_REJECT_ICMP_UNREACH:
	407	case NFT_REJECT_ICMPX_UNREACH:
	408	if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
	409	goto nla_put_failure;
	410	break;
c1f86676 DM	411	default:
c1f86676 DM	412	break;
51b0a5d8 PNA	413	}
	414
	415	return 0;
	416
	417	nla_put_failure:
	418	return -1;
85f5b308 PNA	419	}
	420
	421	static struct nft_expr_type nft_reject_bridge_type;
	422	static const struct nft_expr_ops nft_reject_bridge_ops = {
	423	.type = &nft_reject_bridge_type,
	424	.size = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
	425	.eval = nft_reject_bridge_eval,
51b0a5d8 PNA	426	.init = nft_reject_bridge_init,
51b0a5d8 PNA	427	.dump = nft_reject_bridge_dump,
127917c2	428	.validate = nft_reject_bridge_validate,
85f5b308 PNA	429	};
	430
	431	static struct nft_expr_type nft_reject_bridge_type __read_mostly = {
	432	.family = NFPROTO_BRIDGE,
	433	.name = "reject",
	434	.ops = &nft_reject_bridge_ops,
	435	.policy = nft_reject_policy,
	436	.maxattr = NFTA_REJECT_MAX,
	437	.owner = THIS_MODULE,
	438	};
	439
	440	static int __init nft_reject_bridge_module_init(void)
	441	{
	442	return nft_register_expr(&nft_reject_bridge_type);
	443	}
	444
	445	static void __exit nft_reject_bridge_module_exit(void)
	446	{
	447	nft_unregister_expr(&nft_reject_bridge_type);
	448	}
	449
	450	module_init(nft_reject_bridge_module_init);
	451	module_exit(nft_reject_bridge_module_exit);
	452
	453	MODULE_LICENSE("GPL");
	454	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
	455	MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "reject");