[linux-2.6-block.git] / net / sched / act_csum.c

/*
 * Checksum updating actions
 *
 * Copyright (c) 2010 Gregoire Baron <baronchon@n7mm.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */

#include <linux/types.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spinlock.h>

#include <linux/netlink.h>
#include <net/netlink.h>
#include <linux/rtnetlink.h>

#include <linux/skbuff.h>

#include <net/ip.h>
#include <net/ipv6.h>
#include <net/icmp.h>
#include <linux/icmpv6.h>
#include <linux/igmp.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <net/ip6_checksum.h>

#include <net/act_api.h>

#include <linux/tc_act/tc_csum.h>
#include <net/tc_act/tc_csum.h>

#define CSUM_TAB_MASK 15

static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
	[TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
};

static int tcf_csum_init(struct net *n, struct nlattr *nla, struct nlattr *est,
			 struct tc_action *a, int ovr, int bind)
{
	struct nlattr *tb[TCA_CSUM_MAX + 1];
	struct tc_csum *parm;
	struct tcf_csum *p;
	int ret = 0, err;

	if (nla == NULL)
		return -EINVAL;

	err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy);
	if (err < 0)
		return err;

	if (tb[TCA_CSUM_PARMS] == NULL)
		return -EINVAL;
	parm = nla_data(tb[TCA_CSUM_PARMS]);

	if (!tcf_hash_check(parm->index, a, bind)) {
		ret = tcf_hash_create(parm->index, est, a, sizeof(*p), bind);
		if (ret)
			return ret;
		ret = ACT_P_CREATED;
	} else {
		if (bind)/* dont override defaults */
			return 0;
		tcf_hash_release(a, bind);
		if (!ovr)
			return -EEXIST;
	}

	p = to_tcf_csum(a);
	spin_lock_bh(&p->tcf_lock);
	p->tcf_action = parm->action;
	p->update_flags = parm->update_flags;
	spin_unlock_bh(&p->tcf_lock);

	if (ret == ACT_P_CREATED)
		tcf_hash_insert(a);

	return ret;
}

/**
 * tcf_csum_skb_nextlayer - Get next layer pointer
 * @skb: sk_buff to use
 * @ihl: previous summed headers length
 * @ipl: complete packet length
 * @jhl: next header length
 *
 * Check the expected next layer availability in the specified sk_buff.
 * Return the next layer pointer if pass, NULL otherwise.
 */
static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
				    unsigned int ihl, unsigned int ipl,
				    unsigned int jhl)
{
	int ntkoff = skb_network_offset(skb);
	int hl = ihl + jhl;

	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
	    (skb_cloned(skb) &&
	     !skb_clone_writable(skb, hl + ntkoff) &&
	     pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
		return NULL;
	else
		return (void *)(skb_network_header(skb) + ihl);
}

static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
			      unsigned int ihl, unsigned int ipl)
{
	struct icmphdr *icmph;

	icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
	if (icmph == NULL)
		return 0;

	icmph->checksum = 0;
	skb->csum = csum_partial(icmph, ipl - ihl, 0);
	icmph->checksum = csum_fold(skb->csum);

	skb->ip_summed = CHECKSUM_NONE;

	return 1;
}

static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
			      unsigned int ihl, unsigned int ipl)
{
	struct igmphdr *igmph;

	igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
	if (igmph == NULL)
		return 0;

	igmph->csum = 0;
	skb->csum = csum_partial(igmph, ipl - ihl, 0);
	igmph->csum = csum_fold(skb->csum);

	skb->ip_summed = CHECKSUM_NONE;

	return 1;
}

static int tcf_csum_ipv6_icmp(struct sk_buff *skb,
			      unsigned int ihl, unsigned int ipl)
{
	struct icmp6hdr *icmp6h;
	const struct ipv6hdr *ip6h;

	icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
	if (icmp6h == NULL)
		return 0;

	ip6h = ipv6_hdr(skb);
	icmp6h->icmp6_cksum = 0;
	skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
	icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
					      ipl - ihl, IPPROTO_ICMPV6,
					      skb->csum);

	skb->ip_summed = CHECKSUM_NONE;

	return 1;
}

static int tcf_csum_ipv4_tcp(struct sk_buff *skb,
			     unsigned int ihl, unsigned int ipl)
{
	struct tcphdr *tcph;
	const struct iphdr *iph;

	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
	if (tcph == NULL)
		return 0;

	iph = ip_hdr(skb);
	tcph->check = 0;
	skb->csum = csum_partial(tcph, ipl - ihl, 0);
	tcph->check = tcp_v4_check(ipl - ihl,
				   iph->saddr, iph->daddr, skb->csum);

	skb->ip_summed = CHECKSUM_NONE;

	return 1;
}

static int tcf_csum_ipv6_tcp(struct sk_buff *skb,
			     unsigned int ihl, unsigned int ipl)
{
	struct tcphdr *tcph;
	const struct ipv6hdr *ip6h;

	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
	if (tcph == NULL)
		return 0;

	ip6h = ipv6_hdr(skb);
	tcph->check = 0;
	skb->csum = csum_partial(tcph, ipl - ihl, 0);
	tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
				      ipl - ihl, IPPROTO_TCP,
				      skb->csum);

	skb->ip_summed = CHECKSUM_NONE;

	return 1;
}

static int tcf_csum_ipv4_udp(struct sk_buff *skb,
			     unsigned int ihl, unsigned int ipl, int udplite)
{
	struct udphdr *udph;
	const struct iphdr *iph;
	u16 ul;

	/*
	 * Support both UDP and UDPLITE checksum algorithms, Don't use
	 * udph->len to get the real length without any protocol check,
	 * UDPLITE uses udph->len for another thing,
	 * Use iph->tot_len, or just ipl.
	 */

	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
	if (udph == NULL)
		return 0;

	iph = ip_hdr(skb);
	ul = ntohs(udph->len);

	if (udplite || udph->check) {

		udph->check = 0;

		if (udplite) {
			if (ul == 0)
				skb->csum = csum_partial(udph, ipl - ihl, 0);
			else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
				skb->csum = csum_partial(udph, ul, 0);
			else
				goto ignore_obscure_skb;
		} else {
			if (ul != ipl - ihl)
				goto ignore_obscure_skb;

			skb->csum = csum_partial(udph, ul, 0);
		}

		udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
						ul, iph->protocol,
						skb->csum);

		if (!udph->check)
			udph->check = CSUM_MANGLED_0;
	}

	skb->ip_summed = CHECKSUM_NONE;

ignore_obscure_skb:
	return 1;
}

static int tcf_csum_ipv6_udp(struct sk_buff *skb,
			     unsigned int ihl, unsigned int ipl, int udplite)
{
	struct udphdr *udph;
	const struct ipv6hdr *ip6h;
	u16 ul;

	/*
	 * Support both UDP and UDPLITE checksum algorithms, Don't use
	 * udph->len to get the real length without any protocol check,
	 * UDPLITE uses udph->len for another thing,
	 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
	 */

	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
	if (udph == NULL)
		return 0;

	ip6h = ipv6_hdr(skb);
	ul = ntohs(udph->len);

	udph->check = 0;

	if (udplite) {
		if (ul == 0)
			skb->csum = csum_partial(udph, ipl - ihl, 0);

		else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
			skb->csum = csum_partial(udph, ul, 0);

		else
			goto ignore_obscure_skb;
	} else {
		if (ul != ipl - ihl)
			goto ignore_obscure_skb;

		skb->csum = csum_partial(udph, ul, 0);
	}

	udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
				      udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
				      skb->csum);

	if (!udph->check)
		udph->check = CSUM_MANGLED_0;

	skb->ip_summed = CHECKSUM_NONE;

ignore_obscure_skb:
	return 1;
}

static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
{
	const struct iphdr *iph;
	int ntkoff;

	ntkoff = skb_network_offset(skb);

	if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
		goto fail;

	iph = ip_hdr(skb);

	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
	case IPPROTO_ICMP:
		if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
			if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
						ntohs(iph->tot_len)))
				goto fail;
		break;
	case IPPROTO_IGMP:
		if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
			if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
						ntohs(iph->tot_len)))
				goto fail;
		break;
	case IPPROTO_TCP:
		if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
			if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
					       ntohs(iph->tot_len)))
				goto fail;
		break;
	case IPPROTO_UDP:
		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
					       ntohs(iph->tot_len), 0))
				goto fail;
		break;
	case IPPROTO_UDPLITE:
		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
					       ntohs(iph->tot_len), 1))
				goto fail;
		break;
	}

	if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
		if (skb_cloned(skb) &&
		    !skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
		    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
			goto fail;

		ip_send_check(ip_hdr(skb));
	}

	return 1;

fail:
	return 0;
}

static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
				 unsigned int ixhl, unsigned int *pl)
{
	int off, len, optlen;
	unsigned char *xh = (void *)ip6xh;

	off = sizeof(*ip6xh);
	len = ixhl - off;

	while (len > 1) {
		switch (xh[off]) {
		case IPV6_TLV_PAD1:
			optlen = 1;
			break;
		case IPV6_TLV_JUMBO:
			optlen = xh[off + 1] + 2;
			if (optlen != 6 || len < 6 || (off & 3) != 2)
				/* wrong jumbo option length/alignment */
				return 0;
			*pl = ntohl(*(__be32 *)(xh + off + 2));
			goto done;
		default:
			optlen = xh[off + 1] + 2;
			if (optlen > len)
				/* ignore obscure options */
				goto done;
			break;
		}
		off += optlen;
		len -= optlen;
	}

done:
	return 1;
}

static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
{
	struct ipv6hdr *ip6h;
	struct ipv6_opt_hdr *ip6xh;
	unsigned int hl, ixhl;
	unsigned int pl;
	int ntkoff;
	u8 nexthdr;

	ntkoff = skb_network_offset(skb);

	hl = sizeof(*ip6h);

	if (!pskb_may_pull(skb, hl + ntkoff))
		goto fail;

	ip6h = ipv6_hdr(skb);

	pl = ntohs(ip6h->payload_len);
	nexthdr = ip6h->nexthdr;

	do {
		switch (nexthdr) {
		case NEXTHDR_FRAGMENT:
			goto ignore_skb;
		case NEXTHDR_ROUTING:
		case NEXTHDR_HOP:
		case NEXTHDR_DEST:
			if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
				goto fail;
			ip6xh = (void *)(skb_network_header(skb) + hl);
			ixhl = ipv6_optlen(ip6xh);
			if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
				goto fail;
			ip6xh = (void *)(skb_network_header(skb) + hl);
			if ((nexthdr == NEXTHDR_HOP) &&
			    !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
				goto fail;
			nexthdr = ip6xh->nexthdr;
			hl += ixhl;
			break;
		case IPPROTO_ICMPV6:
			if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
				if (!tcf_csum_ipv6_icmp(skb,
							hl, pl + sizeof(*ip6h)))
					goto fail;
			goto done;
		case IPPROTO_TCP:
			if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
				if (!tcf_csum_ipv6_tcp(skb,
						       hl, pl + sizeof(*ip6h)))
					goto fail;
			goto done;
		case IPPROTO_UDP:
			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
				if (!tcf_csum_ipv6_udp(skb, hl,
						       pl + sizeof(*ip6h), 0))
					goto fail;
			goto done;
		case IPPROTO_UDPLITE:
			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
				if (!tcf_csum_ipv6_udp(skb, hl,
						       pl + sizeof(*ip6h), 1))
					goto fail;
			goto done;
		default:
			goto ignore_skb;
		}
	} while (pskb_may_pull(skb, hl + 1 + ntkoff));

done:
ignore_skb:
	return 1;

fail:
	return 0;
}

static int tcf_csum(struct sk_buff *skb,
		    const struct tc_action *a, struct tcf_result *res)
{
	struct tcf_csum *p = a->priv;
	int action;
	u32 update_flags;

	spin_lock(&p->tcf_lock);
	p->tcf_tm.lastuse = jiffies;
	bstats_update(&p->tcf_bstats, skb);
	action = p->tcf_action;
	update_flags = p->update_flags;
	spin_unlock(&p->tcf_lock);

	if (unlikely(action == TC_ACT_SHOT))
		goto drop;

	switch (tc_skb_protocol(skb)) {
	case cpu_to_be16(ETH_P_IP):
		if (!tcf_csum_ipv4(skb, update_flags))
			goto drop;
		break;
	case cpu_to_be16(ETH_P_IPV6):
		if (!tcf_csum_ipv6(skb, update_flags))
			goto drop;
		break;
	}

	return action;

drop:
	spin_lock(&p->tcf_lock);
	p->tcf_qstats.drops++;
	spin_unlock(&p->tcf_lock);
	return TC_ACT_SHOT;
}

static int tcf_csum_dump(struct sk_buff *skb,
			 struct tc_action *a, int bind, int ref)
{
	unsigned char *b = skb_tail_pointer(skb);
	struct tcf_csum *p = a->priv;
	struct tc_csum opt = {
		.update_flags = p->update_flags,
		.index   = p->tcf_index,
		.action  = p->tcf_action,
		.refcnt  = p->tcf_refcnt - ref,
		.bindcnt = p->tcf_bindcnt - bind,
	};
	struct tcf_t t;

	if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
		goto nla_put_failure;
	t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
	t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
	t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
	if (nla_put(skb, TCA_CSUM_TM, sizeof(t), &t))
		goto nla_put_failure;

	return skb->len;

nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
}

static struct tc_action_ops act_csum_ops = {
	.kind		= "csum",
	.type		= TCA_ACT_CSUM,
	.owner		= THIS_MODULE,
	.act		= tcf_csum,
	.dump		= tcf_csum_dump,
	.init		= tcf_csum_init,
};

MODULE_DESCRIPTION("Checksum updating actions");
MODULE_LICENSE("GPL");

static int __init csum_init_module(void)
{
	return tcf_register_action(&act_csum_ops, CSUM_TAB_MASK);
}

static void __exit csum_cleanup_module(void)
{
	tcf_unregister_action(&act_csum_ops);
}

module_init(csum_init_module);
module_exit(csum_cleanup_module);
Commit	Line	Data
eb4d4065 GB	1	/*
	2	* Checksum updating actions
	3	*
	4	* Copyright (c) 2010 Gregoire Baron <baronchon@n7mm.org>
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License as published by the Free
	8	* Software Foundation; either version 2 of the License, or (at your option)
	9	* any later version.
	10	*
	11	*/
	12
	13	#include <linux/types.h>
	14	#include <linux/init.h>
	15	#include <linux/kernel.h>
	16	#include <linux/module.h>
	17	#include <linux/spinlock.h>
	18
	19	#include <linux/netlink.h>
	20	#include <net/netlink.h>
	21	#include <linux/rtnetlink.h>
	22
	23	#include <linux/skbuff.h>
	24
	25	#include <net/ip.h>
	26	#include <net/ipv6.h>
	27	#include <net/icmp.h>
	28	#include <linux/icmpv6.h>
	29	#include <linux/igmp.h>
	30	#include <net/tcp.h>
	31	#include <net/udp.h>
2436243a	32	#include <net/ip6_checksum.h>
eb4d4065 GB	33
	34	#include <net/act_api.h>
	35
	36	#include <linux/tc_act/tc_csum.h>
	37	#include <net/tc_act/tc_csum.h>
	38
	39	#define CSUM_TAB_MASK 15
eb4d4065 GB	40
	41	static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
	42	[TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
	43	};
	44
c1b52739	45	static int tcf_csum_init(struct net n, struct nlattr nla, struct nlattr *est,
eb4d4065 GB	46	struct tc_action *a, int ovr, int bind)
	47	{
	48	struct nlattr *tb[TCA_CSUM_MAX + 1];
	49	struct tc_csum *parm;
eb4d4065 GB	50	struct tcf_csum *p;
	51	int ret = 0, err;
	52
	53	if (nla == NULL)
	54	return -EINVAL;
	55
cc7ec456	56	err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy);
eb4d4065 GB	57	if (err < 0)
	58	return err;
	59
	60	if (tb[TCA_CSUM_PARMS] == NULL)
	61	return -EINVAL;
	62	parm = nla_data(tb[TCA_CSUM_PARMS]);
	63
86062033 WC	64	if (!tcf_hash_check(parm->index, a, bind)) {
	65	ret = tcf_hash_create(parm->index, est, a, sizeof(*p), bind);
	66	if (ret)
	67	return ret;
eb4d4065 GB	68	ret = ACT_P_CREATED;
eb4d4065 GB	69	} else {
1a29321e JHS	70	if (bind)/* dont override defaults */
1a29321e JHS	71	return 0;
86062033	72	tcf_hash_release(a, bind);
1a29321e	73	if (!ovr)
eb4d4065	74	return -EEXIST;
eb4d4065 GB	75	}
eb4d4065 GB	76
86062033	77	p = to_tcf_csum(a);
eb4d4065 GB	78	spin_lock_bh(&p->tcf_lock);
	79	p->tcf_action = parm->action;
	80	p->update_flags = parm->update_flags;
	81	spin_unlock_bh(&p->tcf_lock);
	82
	83	if (ret == ACT_P_CREATED)
86062033	84	tcf_hash_insert(a);
eb4d4065 GB	85
	86	return ret;
	87	}
	88
eb4d4065 GB	89	/**
	90	* tcf_csum_skb_nextlayer - Get next layer pointer
	91	* @skb: sk_buff to use
	92	* @ihl: previous summed headers length
	93	* @ipl: complete packet length
	94	* @jhl: next header length
	95	*
	96	* Check the expected next layer availability in the specified sk_buff.
	97	* Return the next layer pointer if pass, NULL otherwise.
	98	*/
	99	static void tcf_csum_skb_nextlayer(struct sk_buff skb,
	100	unsigned int ihl, unsigned int ipl,
	101	unsigned int jhl)
	102	{
	103	int ntkoff = skb_network_offset(skb);
	104	int hl = ihl + jhl;
	105
	106	if (!pskb_may_pull(skb, ipl + ntkoff) \|\| (ipl < hl) \|\|
	107	(skb_cloned(skb) &&
	108	!skb_clone_writable(skb, hl + ntkoff) &&
	109	pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
	110	return NULL;
	111	else
	112	return (void *)(skb_network_header(skb) + ihl);
	113	}
	114
	115	static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
	116	unsigned int ihl, unsigned int ipl)
	117	{
	118	struct icmphdr *icmph;
	119
	120	icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
	121	if (icmph == NULL)
	122	return 0;
	123
	124	icmph->checksum = 0;
	125	skb->csum = csum_partial(icmph, ipl - ihl, 0);
	126	icmph->checksum = csum_fold(skb->csum);
	127
	128	skb->ip_summed = CHECKSUM_NONE;
	129
	130	return 1;
	131	}
	132
	133	static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
	134	unsigned int ihl, unsigned int ipl)
	135	{
	136	struct igmphdr *igmph;
	137
	138	igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
	139	if (igmph == NULL)
	140	return 0;
	141
	142	igmph->csum = 0;
	143	skb->csum = csum_partial(igmph, ipl - ihl, 0);
	144	igmph->csum = csum_fold(skb->csum);
	145
	146	skb->ip_summed = CHECKSUM_NONE;
	147
	148	return 1;
	149	}
	150
d14a489a	151	static int tcf_csum_ipv6_icmp(struct sk_buff *skb,
eb4d4065 GB	152	unsigned int ihl, unsigned int ipl)
	153	{
	154	struct icmp6hdr *icmp6h;
d14a489a	155	const struct ipv6hdr *ip6h;
eb4d4065 GB	156
	157	icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
	158	if (icmp6h == NULL)
	159	return 0;
	160
d14a489a	161	ip6h = ipv6_hdr(skb);
eb4d4065 GB	162	icmp6h->icmp6_cksum = 0;
	163	skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
	164	icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
	165	ipl - ihl, IPPROTO_ICMPV6,
	166	skb->csum);
	167
	168	skb->ip_summed = CHECKSUM_NONE;
	169
	170	return 1;
	171	}
	172
d14a489a	173	static int tcf_csum_ipv4_tcp(struct sk_buff *skb,
eb4d4065 GB	174	unsigned int ihl, unsigned int ipl)
	175	{
	176	struct tcphdr *tcph;
d14a489a	177	const struct iphdr *iph;
eb4d4065 GB	178
	179	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
	180	if (tcph == NULL)
	181	return 0;
	182
d14a489a	183	iph = ip_hdr(skb);
eb4d4065 GB	184	tcph->check = 0;
	185	skb->csum = csum_partial(tcph, ipl - ihl, 0);
	186	tcph->check = tcp_v4_check(ipl - ihl,
	187	iph->saddr, iph->daddr, skb->csum);
	188
	189	skb->ip_summed = CHECKSUM_NONE;
	190
	191	return 1;
	192	}
	193
d14a489a	194	static int tcf_csum_ipv6_tcp(struct sk_buff *skb,
eb4d4065 GB	195	unsigned int ihl, unsigned int ipl)
	196	{
	197	struct tcphdr *tcph;
d14a489a	198	const struct ipv6hdr *ip6h;
eb4d4065 GB	199
	200	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
	201	if (tcph == NULL)
	202	return 0;
	203
d14a489a	204	ip6h = ipv6_hdr(skb);
eb4d4065 GB	205	tcph->check = 0;
	206	skb->csum = csum_partial(tcph, ipl - ihl, 0);
	207	tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
	208	ipl - ihl, IPPROTO_TCP,
	209	skb->csum);
	210
	211	skb->ip_summed = CHECKSUM_NONE;
	212
	213	return 1;
	214	}
	215
d14a489a	216	static int tcf_csum_ipv4_udp(struct sk_buff *skb,
eb4d4065 GB	217	unsigned int ihl, unsigned int ipl, int udplite)
	218	{
	219	struct udphdr *udph;
d14a489a	220	const struct iphdr *iph;
eb4d4065 GB	221	u16 ul;
eb4d4065 GB	222
0eec32ff CG	223	/*
	224	* Support both UDP and UDPLITE checksum algorithms, Don't use
	225	* udph->len to get the real length without any protocol check,
eb4d4065 GB	226	* UDPLITE uses udph->len for another thing,
	227	* Use iph->tot_len, or just ipl.
	228	*/
	229
	230	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
	231	if (udph == NULL)
	232	return 0;
	233
d14a489a	234	iph = ip_hdr(skb);
eb4d4065 GB	235	ul = ntohs(udph->len);
	236
	237	if (udplite \|\| udph->check) {
	238
	239	udph->check = 0;
	240
	241	if (udplite) {
	242	if (ul == 0)
	243	skb->csum = csum_partial(udph, ipl - ihl, 0);
eb4d4065 GB	244	else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
eb4d4065 GB	245	skb->csum = csum_partial(udph, ul, 0);
eb4d4065 GB	246	else
	247	goto ignore_obscure_skb;
	248	} else {
	249	if (ul != ipl - ihl)
	250	goto ignore_obscure_skb;
	251
	252	skb->csum = csum_partial(udph, ul, 0);
	253	}
	254
	255	udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
	256	ul, iph->protocol,
	257	skb->csum);
	258
	259	if (!udph->check)
	260	udph->check = CSUM_MANGLED_0;
	261	}
	262
	263	skb->ip_summed = CHECKSUM_NONE;
	264
	265	ignore_obscure_skb:
	266	return 1;
	267	}
	268
d14a489a	269	static int tcf_csum_ipv6_udp(struct sk_buff *skb,
eb4d4065 GB	270	unsigned int ihl, unsigned int ipl, int udplite)
	271	{
	272	struct udphdr *udph;
d14a489a	273	const struct ipv6hdr *ip6h;
eb4d4065 GB	274	u16 ul;
eb4d4065 GB	275
0eec32ff CG	276	/*
	277	* Support both UDP and UDPLITE checksum algorithms, Don't use
	278	* udph->len to get the real length without any protocol check,
eb4d4065 GB	279	* UDPLITE uses udph->len for another thing,
	280	* Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
	281	*/
	282
	283	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
	284	if (udph == NULL)
	285	return 0;
	286
d14a489a	287	ip6h = ipv6_hdr(skb);
eb4d4065 GB	288	ul = ntohs(udph->len);
	289
	290	udph->check = 0;
	291
	292	if (udplite) {
	293	if (ul == 0)
	294	skb->csum = csum_partial(udph, ipl - ihl, 0);
	295
	296	else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
	297	skb->csum = csum_partial(udph, ul, 0);
	298
	299	else
	300	goto ignore_obscure_skb;
	301	} else {
	302	if (ul != ipl - ihl)
	303	goto ignore_obscure_skb;
	304
	305	skb->csum = csum_partial(udph, ul, 0);
	306	}
	307
	308	udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
	309	udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
	310	skb->csum);
	311
	312	if (!udph->check)
	313	udph->check = CSUM_MANGLED_0;
	314
	315	skb->ip_summed = CHECKSUM_NONE;
	316
	317	ignore_obscure_skb:
	318	return 1;
	319	}
	320
	321	static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
	322	{
d14a489a	323	const struct iphdr *iph;
eb4d4065 GB	324	int ntkoff;
	325
	326	ntkoff = skb_network_offset(skb);
	327
	328	if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
	329	goto fail;
	330
	331	iph = ip_hdr(skb);
	332
	333	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
	334	case IPPROTO_ICMP:
	335	if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
0eec32ff CG	336	if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
0eec32ff CG	337	ntohs(iph->tot_len)))
eb4d4065 GB	338	goto fail;
	339	break;
	340	case IPPROTO_IGMP:
	341	if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
0eec32ff CG	342	if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
0eec32ff CG	343	ntohs(iph->tot_len)))
eb4d4065 GB	344	goto fail;
	345	break;
	346	case IPPROTO_TCP:
	347	if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
d14a489a	348	if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
0eec32ff	349	ntohs(iph->tot_len)))
eb4d4065 GB	350	goto fail;
	351	break;
	352	case IPPROTO_UDP:
	353	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
d14a489a	354	if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
0eec32ff	355	ntohs(iph->tot_len), 0))
eb4d4065 GB	356	goto fail;
	357	break;
	358	case IPPROTO_UDPLITE:
	359	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
d14a489a	360	if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
0eec32ff	361	ntohs(iph->tot_len), 1))
eb4d4065 GB	362	goto fail;
	363	break;
	364	}
	365
	366	if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
	367	if (skb_cloned(skb) &&
	368	!skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
	369	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
	370	goto fail;
	371
d14a489a	372	ip_send_check(ip_hdr(skb));
eb4d4065 GB	373	}
	374
	375	return 1;
	376
	377	fail:
	378	return 0;
	379	}
	380
	381	static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
0eec32ff	382	unsigned int ixhl, unsigned int *pl)
eb4d4065 GB	383	{
	384	int off, len, optlen;
	385	unsigned char xh = (void )ip6xh;
	386
	387	off = sizeof(*ip6xh);
	388	len = ixhl - off;
	389
	390	while (len > 1) {
0eec32ff	391	switch (xh[off]) {
1de5a71c	392	case IPV6_TLV_PAD1:
eb4d4065 GB	393	optlen = 1;
	394	break;
	395	case IPV6_TLV_JUMBO:
	396	optlen = xh[off + 1] + 2;
	397	if (optlen != 6 \|\| len < 6 \|\| (off & 3) != 2)
	398	/* wrong jumbo option length/alignment */
	399	return 0;
	400	pl = ntohl((__be32 *)(xh + off + 2));
	401	goto done;
	402	default:
	403	optlen = xh[off + 1] + 2;
	404	if (optlen > len)
	405	/* ignore obscure options */
	406	goto done;
	407	break;
	408	}
	409	off += optlen;
	410	len -= optlen;
	411	}
	412
	413	done:
	414	return 1;
	415	}
	416
	417	static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
	418	{
	419	struct ipv6hdr *ip6h;
	420	struct ipv6_opt_hdr *ip6xh;
	421	unsigned int hl, ixhl;
	422	unsigned int pl;
	423	int ntkoff;
	424	u8 nexthdr;
	425
	426	ntkoff = skb_network_offset(skb);
	427
	428	hl = sizeof(*ip6h);
	429
	430	if (!pskb_may_pull(skb, hl + ntkoff))
	431	goto fail;
	432
	433	ip6h = ipv6_hdr(skb);
	434
	435	pl = ntohs(ip6h->payload_len);
	436	nexthdr = ip6h->nexthdr;
	437
	438	do {
	439	switch (nexthdr) {
	440	case NEXTHDR_FRAGMENT:
	441	goto ignore_skb;
	442	case NEXTHDR_ROUTING:
	443	case NEXTHDR_HOP:
	444	case NEXTHDR_DEST:
	445	if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
	446	goto fail;
	447	ip6xh = (void *)(skb_network_header(skb) + hl);
	448	ixhl = ipv6_optlen(ip6xh);
	449	if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
	450	goto fail;
d14a489a	451	ip6xh = (void *)(skb_network_header(skb) + hl);
eb4d4065 GB	452	if ((nexthdr == NEXTHDR_HOP) &&
	453	!(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
	454	goto fail;
	455	nexthdr = ip6xh->nexthdr;
	456	hl += ixhl;
	457	break;
	458	case IPPROTO_ICMPV6:
	459	if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
d14a489a	460	if (!tcf_csum_ipv6_icmp(skb,
eb4d4065 GB	461	hl, pl + sizeof(*ip6h)))
	462	goto fail;
	463	goto done;
	464	case IPPROTO_TCP:
	465	if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
d14a489a	466	if (!tcf_csum_ipv6_tcp(skb,
eb4d4065 GB	467	hl, pl + sizeof(*ip6h)))
	468	goto fail;
	469	goto done;
	470	case IPPROTO_UDP:
	471	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
d14a489a	472	if (!tcf_csum_ipv6_udp(skb, hl,
0eec32ff	473	pl + sizeof(*ip6h), 0))
eb4d4065 GB	474	goto fail;
	475	goto done;
	476	case IPPROTO_UDPLITE:
	477	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
d14a489a	478	if (!tcf_csum_ipv6_udp(skb, hl,
0eec32ff	479	pl + sizeof(*ip6h), 1))
eb4d4065 GB	480	goto fail;
	481	goto done;
	482	default:
	483	goto ignore_skb;
	484	}
	485	} while (pskb_may_pull(skb, hl + 1 + ntkoff));
	486
	487	done:
	488	ignore_skb:
	489	return 1;
	490
	491	fail:
	492	return 0;
	493	}
	494
	495	static int tcf_csum(struct sk_buff *skb,
dc7f9f6e	496	const struct tc_action a, struct tcf_result res)
eb4d4065 GB	497	{
	498	struct tcf_csum *p = a->priv;
	499	int action;
	500	u32 update_flags;
	501
	502	spin_lock(&p->tcf_lock);
	503	p->tcf_tm.lastuse = jiffies;
bfe0d029	504	bstats_update(&p->tcf_bstats, skb);
eb4d4065 GB	505	action = p->tcf_action;
	506	update_flags = p->update_flags;
	507	spin_unlock(&p->tcf_lock);
	508
	509	if (unlikely(action == TC_ACT_SHOT))
	510	goto drop;
	511
d8b9605d	512	switch (tc_skb_protocol(skb)) {
eb4d4065 GB	513	case cpu_to_be16(ETH_P_IP):
	514	if (!tcf_csum_ipv4(skb, update_flags))
	515	goto drop;
	516	break;
	517	case cpu_to_be16(ETH_P_IPV6):
	518	if (!tcf_csum_ipv6(skb, update_flags))
	519	goto drop;
	520	break;
	521	}
	522
	523	return action;
	524
	525	drop:
	526	spin_lock(&p->tcf_lock);
	527	p->tcf_qstats.drops++;
	528	spin_unlock(&p->tcf_lock);
	529	return TC_ACT_SHOT;
	530	}
	531
	532	static int tcf_csum_dump(struct sk_buff *skb,
	533	struct tc_action *a, int bind, int ref)
	534	{
	535	unsigned char *b = skb_tail_pointer(skb);
	536	struct tcf_csum *p = a->priv;
	537	struct tc_csum opt = {
	538	.update_flags = p->update_flags,
eb4d4065 GB	539	.index = p->tcf_index,
	540	.action = p->tcf_action,
	541	.refcnt = p->tcf_refcnt - ref,
	542	.bindcnt = p->tcf_bindcnt - bind,
	543	};
	544	struct tcf_t t;
	545
1b34ec43 DM	546	if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
1b34ec43 DM	547	goto nla_put_failure;
eb4d4065 GB	548	t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
	549	t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
	550	t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
1b34ec43 DM	551	if (nla_put(skb, TCA_CSUM_TM, sizeof(t), &t))
1b34ec43 DM	552	goto nla_put_failure;
eb4d4065 GB	553
	554	return skb->len;
	555
	556	nla_put_failure:
	557	nlmsg_trim(skb, b);
	558	return -1;
	559	}
	560
	561	static struct tc_action_ops act_csum_ops = {
0eec32ff	562	.kind = "csum",
0eec32ff	563	.type = TCA_ACT_CSUM,
0eec32ff CG	564	.owner = THIS_MODULE,
	565	.act = tcf_csum,
	566	.dump = tcf_csum_dump,
0eec32ff	567	.init = tcf_csum_init,
eb4d4065 GB	568	};
	569
	570	MODULE_DESCRIPTION("Checksum updating actions");
	571	MODULE_LICENSE("GPL");
	572
	573	static int __init csum_init_module(void)
	574	{
4f1e9d89	575	return tcf_register_action(&act_csum_ops, CSUM_TAB_MASK);
eb4d4065 GB	576	}
	577
	578	static void __exit csum_cleanup_module(void)
	579	{
	580	tcf_unregister_action(&act_csum_ops);
	581	}
	582
	583	module_init(csum_init_module);
	584	module_exit(csum_cleanup_module);