[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 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,
				   sysctl_ip_default_ttl);
	nf_reject_ip_tcphdr_put(nskb, oldskb, oth);
	niph->ttl	= 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 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,
				   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);
	struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out);
	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->skb, pkt->in,
						      pkt->hook,
						      priv->icmp_code);
			break;
		case NFT_REJECT_TCP_RST:
			nft_reject_br_send_v4_tcp_reset(pkt->skb, pkt->in,
							pkt->hook);
			break;
		case NFT_REJECT_ICMPX_UNREACH:
			nft_reject_br_send_v4_unreach(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(net, pkt->skb, pkt->in,
						      pkt->hook,
						      priv->icmp_code);
			break;
		case NFT_REJECT_TCP_RST:
			nft_reject_br_send_v6_tcp_reset(net, pkt->skb, pkt->in,
							pkt->hook);
			break;
		case NFT_REJECT_ICMPX_UNREACH:
			nft_reject_br_send_v6_unreach(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	*/
	43	static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb,
	44	const struct net_device *dev,
	45	int hook)
523b929d PNA	46	{
	47	struct sk_buff *nskb;
	48	struct iphdr *niph;
	49	const struct tcphdr *oth;
	50	struct tcphdr _oth;
	51
68b0faa8	52	if (!nft_bridge_iphdr_validate(oldskb))
523b929d PNA	53	return;
	54
	55	oth = nf_reject_ip_tcphdr_get(oldskb, &_oth, hook);
	56	if (!oth)
	57	return;
	58
	59	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
	60	LL_MAX_HEADER, GFP_ATOMIC);
	61	if (!nskb)
	62	return;
	63
	64	skb_reserve(nskb, LL_MAX_HEADER);
	65	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_TCP,
	66	sysctl_ip_default_ttl);
	67	nf_reject_ip_tcphdr_put(nskb, oldskb, oth);
	68	niph->ttl = sysctl_ip_default_ttl;
	69	niph->tot_len = htons(nskb->len);
	70	ip_send_check(niph);
	71
	72	nft_reject_br_push_etherhdr(oldskb, nskb);
	73
72500bc1	74	br_deliver(br_port_get_rcu(dev), nskb);
523b929d PNA	75	}
523b929d PNA	76
72500bc1 FW	77	static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb,
	78	const struct net_device *dev,
	79	int hook, u8 code)
523b929d PNA	80	{
	81	struct sk_buff *nskb;
	82	struct iphdr *niph;
	83	struct icmphdr *icmph;
	84	unsigned int len;
	85	void *payload;
	86	__wsum csum;
72500bc1	87	u8 proto;
523b929d	88
72500bc1	89	if (oldskb->csum_bad \|\| !nft_bridge_iphdr_validate(oldskb))
523b929d PNA	90	return;
	91
	92	/* IP header checks: fragment. */
	93	if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
	94	return;
	95
	96	/* RFC says return as much as we can without exceeding 576 bytes. */
	97	len = min_t(unsigned int, 536, oldskb->len);
	98
	99	if (!pskb_may_pull(oldskb, len))
	100	return;
	101
a03a8dbe	102	if (pskb_trim_rcsum(oldskb, ntohs(ip_hdr(oldskb)->tot_len)))
72500bc1 FW	103	return;
	104
	105	if (ip_hdr(oldskb)->protocol == IPPROTO_TCP \|\|
	106	ip_hdr(oldskb)->protocol == IPPROTO_UDP)
	107	proto = ip_hdr(oldskb)->protocol;
	108	else
	109	proto = 0;
	110
	111	if (!skb_csum_unnecessary(oldskb) &&
	112	nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), proto))
523b929d PNA	113	return;
	114
	115	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmphdr) +
	116	LL_MAX_HEADER + len, GFP_ATOMIC);
	117	if (!nskb)
	118	return;
	119
	120	skb_reserve(nskb, LL_MAX_HEADER);
	121	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_ICMP,
	122	sysctl_ip_default_ttl);
	123
	124	skb_reset_transport_header(nskb);
	125	icmph = (struct icmphdr *)skb_put(nskb, sizeof(struct icmphdr));
	126	memset(icmph, 0, sizeof(*icmph));
	127	icmph->type = ICMP_DEST_UNREACH;
	128	icmph->code = code;
	129
	130	payload = skb_put(nskb, len);
	131	memcpy(payload, skb_network_header(oldskb), len);
	132
	133	csum = csum_partial((void *)icmph, len + sizeof(struct icmphdr), 0);
	134	icmph->checksum = csum_fold(csum);
	135
	136	niph->tot_len = htons(nskb->len);
	137	ip_send_check(niph);
	138
	139	nft_reject_br_push_etherhdr(oldskb, nskb);
	140
72500bc1	141	br_deliver(br_port_get_rcu(dev), nskb);
523b929d PNA	142	}
523b929d PNA	143
523b929d	144	static void nft_reject_br_send_v6_tcp_reset(struct net *net,
72500bc1 FW	145	struct sk_buff *oldskb,
	146	const struct net_device *dev,
	147	int hook)
523b929d PNA	148	{
	149	struct sk_buff *nskb;
	150	const struct tcphdr *oth;
	151	struct tcphdr _oth;
	152	unsigned int otcplen;
	153	struct ipv6hdr *nip6h;
	154
68b0faa8	155	if (!nft_bridge_ip6hdr_validate(oldskb))
523b929d PNA	156	return;
	157
	158	oth = nf_reject_ip6_tcphdr_get(oldskb, &_oth, &otcplen, hook);
	159	if (!oth)
	160	return;
	161
	162	nskb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(struct tcphdr) +
	163	LL_MAX_HEADER, GFP_ATOMIC);
	164	if (!nskb)
	165	return;
	166
	167	skb_reserve(nskb, LL_MAX_HEADER);
	168	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP,
	169	net->ipv6.devconf_all->hop_limit);
	170	nf_reject_ip6_tcphdr_put(nskb, oldskb, oth, otcplen);
	171	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
	172
	173	nft_reject_br_push_etherhdr(oldskb, nskb);
	174
72500bc1 FW	175	br_deliver(br_port_get_rcu(dev), nskb);
	176	}
	177
	178	static bool reject6_br_csum_ok(struct sk_buff *skb, int hook)
	179	{
	180	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
	181	int thoff;
	182	__be16 fo;
	183	u8 proto = ip6h->nexthdr;
	184
	185	if (skb->csum_bad)
	186	return false;
	187
	188	if (skb_csum_unnecessary(skb))
	189	return true;
	190
	191	if (ip6h->payload_len &&
	192	pskb_trim_rcsum(skb, ntohs(ip6h->payload_len) + sizeof(*ip6h)))
	193	return false;
	194
	195	thoff = ipv6_skip_exthdr(skb, ((u8*)(ip6h+1) - skb->data), &proto, &fo);
	196	if (thoff < 0 \|\| thoff >= skb->len \|\| (fo & htons(~0x7)) != 0)
	197	return false;
	198
	199	return nf_ip6_checksum(skb, hook, thoff, proto) == 0;
523b929d PNA	200	}
	201
	202	static void nft_reject_br_send_v6_unreach(struct net *net,
72500bc1 FW	203	struct sk_buff *oldskb,
	204	const struct net_device *dev,
	205	int hook, u8 code)
523b929d PNA	206	{
	207	struct sk_buff *nskb;
	208	struct ipv6hdr *nip6h;
	209	struct icmp6hdr *icmp6h;
	210	unsigned int len;
	211	void *payload;
	212
68b0faa8	213	if (!nft_bridge_ip6hdr_validate(oldskb))
523b929d PNA	214	return;
	215
	216	/* Include "As much of invoking packet as possible without the ICMPv6
	217	* packet exceeding the minimum IPv6 MTU" in the ICMP payload.
	218	*/
	219	len = min_t(unsigned int, 1220, oldskb->len);
	220
	221	if (!pskb_may_pull(oldskb, len))
	222	return;
	223
72500bc1 FW	224	if (!reject6_br_csum_ok(oldskb, hook))
	225	return;
	226
523b929d PNA	227	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmp6hdr) +
	228	LL_MAX_HEADER + len, GFP_ATOMIC);
	229	if (!nskb)
	230	return;
	231
	232	skb_reserve(nskb, LL_MAX_HEADER);
	233	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_ICMPV6,
	234	net->ipv6.devconf_all->hop_limit);
	235
	236	skb_reset_transport_header(nskb);
	237	icmp6h = (struct icmp6hdr *)skb_put(nskb, sizeof(struct icmp6hdr));
	238	memset(icmp6h, 0, sizeof(*icmp6h));
	239	icmp6h->icmp6_type = ICMPV6_DEST_UNREACH;
	240	icmp6h->icmp6_code = code;
	241
	242	payload = skb_put(nskb, len);
	243	memcpy(payload, skb_network_header(oldskb), len);
	244	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
	245
	246	icmp6h->icmp6_cksum =
	247	csum_ipv6_magic(&nip6h->saddr, &nip6h->daddr,
	248	nskb->len - sizeof(struct ipv6hdr),
	249	IPPROTO_ICMPV6,
	250	csum_partial(icmp6h,
	251	nskb->len - sizeof(struct ipv6hdr),
	252	0));
	253
	254	nft_reject_br_push_etherhdr(oldskb, nskb);
	255
72500bc1	256	br_deliver(br_port_get_rcu(dev), nskb);
523b929d	257	}
85f5b308 PNA	258
85f5b308 PNA	259	static void nft_reject_bridge_eval(const struct nft_expr *expr,
a55e22e9 PM	260	struct nft_regs *regs,
a55e22e9 PM	261	const struct nft_pktinfo *pkt)
85f5b308	262	{
51b0a5d8 PNA	263	struct nft_reject *priv = nft_expr_priv(expr);
51b0a5d8 PNA	264	struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out);
523b929d PNA	265	const unsigned char *dest = eth_hdr(pkt->skb)->h_dest;
	266
	267	if (is_broadcast_ether_addr(dest) \|\|
	268	is_multicast_ether_addr(dest))
	269	goto out;
51b0a5d8	270
85f5b308 PNA	271	switch (eth_hdr(pkt->skb)->h_proto) {
85f5b308 PNA	272	case htons(ETH_P_IP):
51b0a5d8 PNA	273	switch (priv->type) {
51b0a5d8 PNA	274	case NFT_REJECT_ICMP_UNREACH:
72500bc1	275	nft_reject_br_send_v4_unreach(pkt->skb, pkt->in,
6aa187f2	276	pkt->hook,
523b929d	277	priv->icmp_code);
51b0a5d8 PNA	278	break;
51b0a5d8 PNA	279	case NFT_REJECT_TCP_RST:
72500bc1	280	nft_reject_br_send_v4_tcp_reset(pkt->skb, pkt->in,
6aa187f2	281	pkt->hook);
51b0a5d8 PNA	282	break;
51b0a5d8 PNA	283	case NFT_REJECT_ICMPX_UNREACH:
72500bc1	284	nft_reject_br_send_v4_unreach(pkt->skb, pkt->in,
6aa187f2	285	pkt->hook,
523b929d	286	nft_reject_icmp_code(priv->icmp_code));
51b0a5d8 PNA	287	break;
	288	}
	289	break;
85f5b308	290	case htons(ETH_P_IPV6):
51b0a5d8 PNA	291	switch (priv->type) {
51b0a5d8 PNA	292	case NFT_REJECT_ICMP_UNREACH:
72500bc1	293	nft_reject_br_send_v6_unreach(net, pkt->skb, pkt->in,
6aa187f2	294	pkt->hook,
523b929d	295	priv->icmp_code);
51b0a5d8 PNA	296	break;
51b0a5d8 PNA	297	case NFT_REJECT_TCP_RST:
72500bc1	298	nft_reject_br_send_v6_tcp_reset(net, pkt->skb, pkt->in,
6aa187f2	299	pkt->hook);
51b0a5d8 PNA	300	break;
51b0a5d8 PNA	301	case NFT_REJECT_ICMPX_UNREACH:
72500bc1	302	nft_reject_br_send_v6_unreach(net, pkt->skb, pkt->in,
6aa187f2	303	pkt->hook,
523b929d	304	nft_reject_icmpv6_code(priv->icmp_code));
51b0a5d8 PNA	305	break;
	306	}
	307	break;
85f5b308 PNA	308	default:
85f5b308 PNA	309	/* No explicit way to reject this protocol, drop it. */
85f5b308 PNA	310	break;
85f5b308 PNA	311	}
523b929d	312	out:
a55e22e9	313	regs->verdict.code = NF_DROP;
51b0a5d8 PNA	314	}
51b0a5d8 PNA	315
75e8d06d PNA	316	static int nft_reject_bridge_validate(const struct nft_ctx *ctx,
	317	const struct nft_expr *expr,
	318	const struct nft_data **data)
127917c2	319	{
75e8d06d PNA	320	return nft_chain_validate_hooks(ctx->chain, (1 << NF_BR_PRE_ROUTING) \|
75e8d06d PNA	321	(1 << NF_BR_LOCAL_IN));
127917c2 PNA	322	}
127917c2 PNA	323
51b0a5d8 PNA	324	static int nft_reject_bridge_init(const struct nft_ctx *ctx,
	325	const struct nft_expr *expr,
	326	const struct nlattr * const tb[])
	327	{
	328	struct nft_reject *priv = nft_expr_priv(expr);
127917c2 PNA	329	int icmp_code, err;
127917c2 PNA	330
75e8d06d	331	err = nft_reject_bridge_validate(ctx, expr, NULL);
127917c2 PNA	332	if (err < 0)
127917c2 PNA	333	return err;
51b0a5d8 PNA	334
	335	if (tb[NFTA_REJECT_TYPE] == NULL)
	336	return -EINVAL;
	337
	338	priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
	339	switch (priv->type) {
	340	case NFT_REJECT_ICMP_UNREACH:
	341	case NFT_REJECT_ICMPX_UNREACH:
	342	if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
	343	return -EINVAL;
	344
	345	icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
	346	if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
	347	icmp_code > NFT_REJECT_ICMPX_MAX)
	348	return -EINVAL;
	349
	350	priv->icmp_code = icmp_code;
	351	break;
	352	case NFT_REJECT_TCP_RST:
	353	break;
	354	default:
	355	return -EINVAL;
	356	}
	357	return 0;
	358	}
	359
	360	static int nft_reject_bridge_dump(struct sk_buff *skb,
	361	const struct nft_expr *expr)
	362	{
	363	const struct nft_reject *priv = nft_expr_priv(expr);
	364
	365	if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
	366	goto nla_put_failure;
	367
	368	switch (priv->type) {
	369	case NFT_REJECT_ICMP_UNREACH:
	370	case NFT_REJECT_ICMPX_UNREACH:
	371	if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
	372	goto nla_put_failure;
	373	break;
c1f86676 DM	374	default:
c1f86676 DM	375	break;
51b0a5d8 PNA	376	}
	377
	378	return 0;
	379
	380	nla_put_failure:
	381	return -1;
85f5b308 PNA	382	}
	383
	384	static struct nft_expr_type nft_reject_bridge_type;
	385	static const struct nft_expr_ops nft_reject_bridge_ops = {
	386	.type = &nft_reject_bridge_type,
	387	.size = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
	388	.eval = nft_reject_bridge_eval,
51b0a5d8 PNA	389	.init = nft_reject_bridge_init,
51b0a5d8 PNA	390	.dump = nft_reject_bridge_dump,
127917c2	391	.validate = nft_reject_bridge_validate,
85f5b308 PNA	392	};
	393
	394	static struct nft_expr_type nft_reject_bridge_type __read_mostly = {
	395	.family = NFPROTO_BRIDGE,
	396	.name = "reject",
	397	.ops = &nft_reject_bridge_ops,
	398	.policy = nft_reject_policy,
	399	.maxattr = NFTA_REJECT_MAX,
	400	.owner = THIS_MODULE,
	401	};
	402
	403	static int __init nft_reject_bridge_module_init(void)
	404	{
	405	return nft_register_expr(&nft_reject_bridge_type);
	406	}
	407
	408	static void __exit nft_reject_bridge_module_exit(void)
	409	{
	410	nft_unregister_expr(&nft_reject_bridge_type);
	411	}
	412
	413	module_init(nft_reject_bridge_module_init);
	414	module_exit(nft_reject_bridge_module_exit);
	415
	416	MODULE_LICENSE("GPL");
	417	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
	418	MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "reject");