[net-next-2.6.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 struct tcf_common *tcf_csum_ht[CSUM_TAB_MASK + 1];
static u32 csum_idx_gen;
static DEFINE_RWLOCK(csum_lock);

static struct tcf_hashinfo csum_hash_info = {
	.htab	= tcf_csum_ht,
	.hmask	= CSUM_TAB_MASK,
	.lock	= &csum_lock,
};

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 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_common *pc;
	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]);

	pc = tcf_hash_check(parm->index, a, bind, &csum_hash_info);
	if (!pc) {
		pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
				     &csum_idx_gen, &csum_hash_info);
		if (IS_ERR(pc))
			return PTR_ERR(pc);
		p = to_tcf_csum(pc);
		ret = ACT_P_CREATED;
	} else {
		p = to_tcf_csum(pc);
		if (!ovr) {
			tcf_hash_release(pc, bind, &csum_hash_info);
			return -EEXIST;
		}
	}

	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(pc, &csum_hash_info);

	return ret;
}

static int tcf_csum_cleanup(struct tc_action *a, int bind)
{
	struct tcf_csum *p = a->priv;
	return tcf_hash_release(&p->common, bind, &csum_hash_info);
}

/**
 * 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, struct ipv6hdr *ip6h,
			      unsigned int ihl, unsigned int ipl)
{
	struct icmp6hdr *icmp6h;

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

	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, struct iphdr *iph,
			     unsigned int ihl, unsigned int ipl)
{
	struct tcphdr *tcph;

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

	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, struct ipv6hdr *ip6h,
			     unsigned int ihl, unsigned int ipl)
{
	struct tcphdr *tcph;

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

	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, struct iphdr *iph,
			     unsigned int ihl, unsigned int ipl, int udplite)
{
	struct udphdr *udph;
	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;

	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, struct ipv6hdr *ip6h,
			     unsigned int ihl, unsigned int ipl, int udplite)
{
	struct udphdr *udph;
	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;

	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)
{
	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, 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, 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, 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(iph);
	}

	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_PAD0:
			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;
			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, ip6h,
							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, ip6h,
						       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, ip6h, 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, ip6h, 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,
		    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;
	p->tcf_bstats.bytes += qdisc_pkt_len(skb);
	p->tcf_bstats.packets++;
	action = p->tcf_action;
	update_flags = p->update_flags;
	spin_unlock(&p->tcf_lock);

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

	switch (skb->protocol) {
	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;

	NLA_PUT(skb, TCA_CSUM_PARMS, sizeof(opt), &opt);
	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);
	NLA_PUT(skb, TCA_CSUM_TM, sizeof(t), &t);

	return skb->len;

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

static struct tc_action_ops act_csum_ops = {
	.kind		= "csum",
	.hinfo		= &csum_hash_info,
	.type		= TCA_ACT_CSUM,
	.capab		= TCA_CAP_NONE,
	.owner		= THIS_MODULE,
	.act		= tcf_csum,
	.dump		= tcf_csum_dump,
	.cleanup	= tcf_csum_cleanup,
	.lookup		= tcf_hash_search,
	.init		= tcf_csum_init,
	.walk		= tcf_generic_walker
};

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

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

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
	40	static struct tcf_common *tcf_csum_ht[CSUM_TAB_MASK + 1];
	41	static u32 csum_idx_gen;
	42	static DEFINE_RWLOCK(csum_lock);
	43
	44	static struct tcf_hashinfo csum_hash_info = {
0eec32ff CG	45	.htab = tcf_csum_ht,
	46	.hmask = CSUM_TAB_MASK,
	47	.lock = &csum_lock,
eb4d4065 GB	48	};
	49
	50	static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
	51	[TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
	52	};
	53
	54	static int tcf_csum_init(struct nlattr nla, struct nlattr est,
	55	struct tc_action *a, int ovr, int bind)
	56	{
	57	struct nlattr *tb[TCA_CSUM_MAX + 1];
	58	struct tc_csum *parm;
	59	struct tcf_common *pc;
	60	struct tcf_csum *p;
	61	int ret = 0, err;
	62
	63	if (nla == NULL)
	64	return -EINVAL;
	65
	66	err = nla_parse_nested(tb, TCA_CSUM_MAX, nla,csum_policy);
	67	if (err < 0)
	68	return err;
	69
	70	if (tb[TCA_CSUM_PARMS] == NULL)
	71	return -EINVAL;
	72	parm = nla_data(tb[TCA_CSUM_PARMS]);
	73
	74	pc = tcf_hash_check(parm->index, a, bind, &csum_hash_info);
	75	if (!pc) {
0eec32ff CG	76	pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
0eec32ff CG	77	&csum_idx_gen, &csum_hash_info);
eb4d4065 GB	78	if (IS_ERR(pc))
	79	return PTR_ERR(pc);
	80	p = to_tcf_csum(pc);
	81	ret = ACT_P_CREATED;
	82	} else {
	83	p = to_tcf_csum(pc);
	84	if (!ovr) {
	85	tcf_hash_release(pc, bind, &csum_hash_info);
	86	return -EEXIST;
	87	}
	88	}
	89
	90	spin_lock_bh(&p->tcf_lock);
	91	p->tcf_action = parm->action;
	92	p->update_flags = parm->update_flags;
	93	spin_unlock_bh(&p->tcf_lock);
	94
	95	if (ret == ACT_P_CREATED)
	96	tcf_hash_insert(pc, &csum_hash_info);
	97
	98	return ret;
	99	}
	100
	101	static int tcf_csum_cleanup(struct tc_action *a, int bind)
	102	{
	103	struct tcf_csum *p = a->priv;
	104	return tcf_hash_release(&p->common, bind, &csum_hash_info);
	105	}
	106
	107	/**
	108	* tcf_csum_skb_nextlayer - Get next layer pointer
	109	* @skb: sk_buff to use
	110	* @ihl: previous summed headers length
	111	* @ipl: complete packet length
	112	* @jhl: next header length
	113	*
	114	* Check the expected next layer availability in the specified sk_buff.
	115	* Return the next layer pointer if pass, NULL otherwise.
	116	*/
	117	static void tcf_csum_skb_nextlayer(struct sk_buff skb,
	118	unsigned int ihl, unsigned int ipl,
	119	unsigned int jhl)
	120	{
	121	int ntkoff = skb_network_offset(skb);
	122	int hl = ihl + jhl;
	123
	124	if (!pskb_may_pull(skb, ipl + ntkoff) \|\| (ipl < hl) \|\|
	125	(skb_cloned(skb) &&
	126	!skb_clone_writable(skb, hl + ntkoff) &&
	127	pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
	128	return NULL;
	129	else
	130	return (void *)(skb_network_header(skb) + ihl);
	131	}
	132
	133	static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
	134	unsigned int ihl, unsigned int ipl)
	135	{
	136	struct icmphdr *icmph;
	137
	138	icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
	139	if (icmph == NULL)
	140	return 0;
	141
142	icmph->checksum = 0;
143	skb->csum = csum_partial(icmph, ipl - ihl, 0);
144	icmph->checksum = csum_fold(skb->csum);
145
146	skb->ip_summed = CHECKSUM_NONE;
147
148	return 1;
149	}
150
151	static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
152	unsigned int ihl, unsigned int ipl)
153	{
154	struct igmphdr *igmph;
155
156	igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
157	if (igmph == NULL)
158	return 0;
159
160	igmph->csum = 0;
161	skb->csum = csum_partial(igmph, ipl - ihl, 0);
162	igmph->csum = csum_fold(skb->csum);
163
164	skb->ip_summed = CHECKSUM_NONE;
165
166	return 1;
167	}
168
169	static int tcf_csum_ipv6_icmp(struct sk_buff skb, struct ipv6hdr ip6h,
170	unsigned int ihl, unsigned int ipl)
171	{
172	struct icmp6hdr *icmp6h;
173
174	icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
175	if (icmp6h == NULL)
176	return 0;
177
178	icmp6h->icmp6_cksum = 0;
179	skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
180	icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
181	ipl - ihl, IPPROTO_ICMPV6,
182	skb->csum);
183
184	skb->ip_summed = CHECKSUM_NONE;
185
186	return 1;
187	}
188
189	static int tcf_csum_ipv4_tcp(struct sk_buff skb, struct iphdr iph,
190	unsigned int ihl, unsigned int ipl)
191	{
192	struct tcphdr *tcph;
193
194	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
195	if (tcph == NULL)
196	return 0;
197
198	tcph->check = 0;
199	skb->csum = csum_partial(tcph, ipl - ihl, 0);
200	tcph->check = tcp_v4_check(ipl - ihl,
201	iph->saddr, iph->daddr, skb->csum);
202
203	skb->ip_summed = CHECKSUM_NONE;
204
205	return 1;
206	}
207
208	static int tcf_csum_ipv6_tcp(struct sk_buff skb, struct ipv6hdr ip6h,
209	unsigned int ihl, unsigned int ipl)
210	{
211	struct tcphdr *tcph;
212
213	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
214	if (tcph == NULL)
215	return 0;
216
217	tcph->check = 0;
218	skb->csum = csum_partial(tcph, ipl - ihl, 0);
219	tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
220	ipl - ihl, IPPROTO_TCP,
221	skb->csum);
222
223	skb->ip_summed = CHECKSUM_NONE;
224
225	return 1;
226	}
227
228	static int tcf_csum_ipv4_udp(struct sk_buff skb, struct iphdr iph,
229	unsigned int ihl, unsigned int ipl, int udplite)
230	{
231	struct udphdr *udph;
232	u16 ul;
233
0eec32ff CG	234	/*
	235	* Support both UDP and UDPLITE checksum algorithms, Don't use
	236	* udph->len to get the real length without any protocol check,
eb4d4065 GB	237	* UDPLITE uses udph->len for another thing,
	238	* Use iph->tot_len, or just ipl.
	239	*/
	240
	241	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
	242	if (udph == NULL)
	243	return 0;
	244
	245	ul = ntohs(udph->len);
	246
	247	if (udplite \|\| udph->check) {
	248
	249	udph->check = 0;
	250
	251	if (udplite) {
	252	if (ul == 0)
	253	skb->csum = csum_partial(udph, ipl - ihl, 0);
eb4d4065 GB	254	else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
eb4d4065 GB	255	skb->csum = csum_partial(udph, ul, 0);
eb4d4065 GB	256	else
	257	goto ignore_obscure_skb;
	258	} else {
	259	if (ul != ipl - ihl)
	260	goto ignore_obscure_skb;
	261
	262	skb->csum = csum_partial(udph, ul, 0);
	263	}
	264
	265	udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
	266	ul, iph->protocol,
	267	skb->csum);
	268
	269	if (!udph->check)
	270	udph->check = CSUM_MANGLED_0;
	271	}
	272
	273	skb->ip_summed = CHECKSUM_NONE;
	274
	275	ignore_obscure_skb:
	276	return 1;
	277	}
	278
	279	static int tcf_csum_ipv6_udp(struct sk_buff skb, struct ipv6hdr ip6h,
	280	unsigned int ihl, unsigned int ipl, int udplite)
	281	{
	282	struct udphdr *udph;
	283	u16 ul;
	284
0eec32ff CG	285	/*
	286	* Support both UDP and UDPLITE checksum algorithms, Don't use
	287	* udph->len to get the real length without any protocol check,
eb4d4065 GB	288	* UDPLITE uses udph->len for another thing,
	289	* Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
	290	*/
	291
	292	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
	293	if (udph == NULL)
	294	return 0;
	295
	296	ul = ntohs(udph->len);
	297
	298	udph->check = 0;
	299
	300	if (udplite) {
	301	if (ul == 0)
	302	skb->csum = csum_partial(udph, ipl - ihl, 0);
	303
	304	else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
	305	skb->csum = csum_partial(udph, ul, 0);
	306
	307	else
	308	goto ignore_obscure_skb;
	309	} else {
	310	if (ul != ipl - ihl)
	311	goto ignore_obscure_skb;
	312
	313	skb->csum = csum_partial(udph, ul, 0);
	314	}
	315
	316	udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
	317	udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
	318	skb->csum);
	319
	320	if (!udph->check)
	321	udph->check = CSUM_MANGLED_0;
	322
	323	skb->ip_summed = CHECKSUM_NONE;
	324
	325	ignore_obscure_skb:
	326	return 1;
	327	}
	328
	329	static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
	330	{
	331	struct iphdr *iph;
	332	int ntkoff;
	333
	334	ntkoff = skb_network_offset(skb);
	335
	336	if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
	337	goto fail;
	338
	339	iph = ip_hdr(skb);
	340
	341	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
	342	case IPPROTO_ICMP:
	343	if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
0eec32ff CG	344	if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
0eec32ff CG	345	ntohs(iph->tot_len)))
eb4d4065 GB	346	goto fail;
	347	break;
	348	case IPPROTO_IGMP:
	349	if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
0eec32ff CG	350	if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
0eec32ff CG	351	ntohs(iph->tot_len)))
eb4d4065 GB	352	goto fail;
	353	break;
	354	case IPPROTO_TCP:
	355	if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
0eec32ff CG	356	if (!tcf_csum_ipv4_tcp(skb, iph, iph->ihl * 4,
0eec32ff CG	357	ntohs(iph->tot_len)))
eb4d4065 GB	358	goto fail;
	359	break;
	360	case IPPROTO_UDP:
	361	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
0eec32ff CG	362	if (!tcf_csum_ipv4_udp(skb, iph, iph->ihl * 4,
0eec32ff CG	363	ntohs(iph->tot_len), 0))
eb4d4065 GB	364	goto fail;
	365	break;
	366	case IPPROTO_UDPLITE:
	367	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
0eec32ff CG	368	if (!tcf_csum_ipv4_udp(skb, iph, iph->ihl * 4,
0eec32ff CG	369	ntohs(iph->tot_len), 1))
eb4d4065 GB	370	goto fail;
	371	break;
	372	}
	373
	374	if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
	375	if (skb_cloned(skb) &&
	376	!skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
	377	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
	378	goto fail;
	379
	380	ip_send_check(iph);
	381	}
	382
	383	return 1;
	384
	385	fail:
	386	return 0;
	387	}
	388
	389	static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
0eec32ff	390	unsigned int ixhl, unsigned int *pl)
eb4d4065 GB	391	{
	392	int off, len, optlen;
	393	unsigned char xh = (void )ip6xh;
	394
	395	off = sizeof(*ip6xh);
	396	len = ixhl - off;
	397
	398	while (len > 1) {
0eec32ff	399	switch (xh[off]) {
eb4d4065 GB	400	case IPV6_TLV_PAD0:
	401	optlen = 1;
	402	break;
	403	case IPV6_TLV_JUMBO:
	404	optlen = xh[off + 1] + 2;
	405	if (optlen != 6 \|\| len < 6 \|\| (off & 3) != 2)
	406	/* wrong jumbo option length/alignment */
	407	return 0;
	408	pl = ntohl((__be32 *)(xh + off + 2));
	409	goto done;
	410	default:
	411	optlen = xh[off + 1] + 2;
	412	if (optlen > len)
	413	/* ignore obscure options */
	414	goto done;
	415	break;
	416	}
	417	off += optlen;
	418	len -= optlen;
	419	}
	420
	421	done:
	422	return 1;
	423	}
	424
	425	static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
	426	{
	427	struct ipv6hdr *ip6h;
	428	struct ipv6_opt_hdr *ip6xh;
	429	unsigned int hl, ixhl;
	430	unsigned int pl;
	431	int ntkoff;
	432	u8 nexthdr;
	433
	434	ntkoff = skb_network_offset(skb);
	435
	436	hl = sizeof(*ip6h);
	437
	438	if (!pskb_may_pull(skb, hl + ntkoff))
	439	goto fail;
	440
	441	ip6h = ipv6_hdr(skb);
	442
	443	pl = ntohs(ip6h->payload_len);
	444	nexthdr = ip6h->nexthdr;
	445
	446	do {
	447	switch (nexthdr) {
	448	case NEXTHDR_FRAGMENT:
	449	goto ignore_skb;
	450	case NEXTHDR_ROUTING:
	451	case NEXTHDR_HOP:
	452	case NEXTHDR_DEST:
	453	if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
	454	goto fail;
	455	ip6xh = (void *)(skb_network_header(skb) + hl);
	456	ixhl = ipv6_optlen(ip6xh);
	457	if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
	458	goto fail;
	459	if ((nexthdr == NEXTHDR_HOP) &&
	460	!(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
	461	goto fail;
	462	nexthdr = ip6xh->nexthdr;
	463	hl += ixhl;
464	break;
465	case IPPROTO_ICMPV6:
466	if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
467	if (!tcf_csum_ipv6_icmp(skb, ip6h,
468	hl, pl + sizeof(*ip6h)))
469	goto fail;
470	goto done;
471	case IPPROTO_TCP:
472	if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
473	if (!tcf_csum_ipv6_tcp(skb, ip6h,
474	hl, pl + sizeof(*ip6h)))
475	goto fail;
476	goto done;
477	case IPPROTO_UDP:
478	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
0eec32ff CG	479	if (!tcf_csum_ipv6_udp(skb, ip6h, hl,
0eec32ff CG	480	pl + sizeof(*ip6h), 0))
eb4d4065 GB	481	goto fail;
	482	goto done;
	483	case IPPROTO_UDPLITE:
	484	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
0eec32ff CG	485	if (!tcf_csum_ipv6_udp(skb, ip6h, hl,
0eec32ff CG	486	pl + sizeof(*ip6h), 1))
eb4d4065 GB	487	goto fail;
	488	goto done;
	489	default:
	490	goto ignore_skb;
	491	}
	492	} while (pskb_may_pull(skb, hl + 1 + ntkoff));
	493
	494	done:
	495	ignore_skb:
	496	return 1;
	497
	498	fail:
	499	return 0;
	500	}
	501
	502	static int tcf_csum(struct sk_buff *skb,
	503	struct tc_action a, struct tcf_result res)
	504	{
	505	struct tcf_csum *p = a->priv;
	506	int action;
	507	u32 update_flags;
	508
	509	spin_lock(&p->tcf_lock);
	510	p->tcf_tm.lastuse = jiffies;
	511	p->tcf_bstats.bytes += qdisc_pkt_len(skb);
	512	p->tcf_bstats.packets++;
	513	action = p->tcf_action;
	514	update_flags = p->update_flags;
	515	spin_unlock(&p->tcf_lock);
	516
	517	if (unlikely(action == TC_ACT_SHOT))
	518	goto drop;
	519
	520	switch (skb->protocol) {
	521	case cpu_to_be16(ETH_P_IP):
	522	if (!tcf_csum_ipv4(skb, update_flags))
	523	goto drop;
	524	break;
	525	case cpu_to_be16(ETH_P_IPV6):
	526	if (!tcf_csum_ipv6(skb, update_flags))
	527	goto drop;
	528	break;
	529	}
	530
	531	return action;
	532
	533	drop:
	534	spin_lock(&p->tcf_lock);
	535	p->tcf_qstats.drops++;
	536	spin_unlock(&p->tcf_lock);
	537	return TC_ACT_SHOT;
	538	}
	539
	540	static int tcf_csum_dump(struct sk_buff *skb,
	541	struct tc_action *a, int bind, int ref)
	542	{
	543	unsigned char *b = skb_tail_pointer(skb);
	544	struct tcf_csum *p = a->priv;
	545	struct tc_csum opt = {
	546	.update_flags = p->update_flags,
eb4d4065 GB	547	.index = p->tcf_index,
	548	.action = p->tcf_action,
	549	.refcnt = p->tcf_refcnt - ref,
	550	.bindcnt = p->tcf_bindcnt - bind,
	551	};
	552	struct tcf_t t;
	553
	554	NLA_PUT(skb, TCA_CSUM_PARMS, sizeof(opt), &opt);
	555	t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
	556	t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
	557	t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
	558	NLA_PUT(skb, TCA_CSUM_TM, sizeof(t), &t);
	559
	560	return skb->len;
	561
	562	nla_put_failure:
	563	nlmsg_trim(skb, b);
	564	return -1;
	565	}
	566
	567	static struct tc_action_ops act_csum_ops = {
0eec32ff CG	568	.kind = "csum",
	569	.hinfo = &csum_hash_info,
	570	.type = TCA_ACT_CSUM,
	571	.capab = TCA_CAP_NONE,
	572	.owner = THIS_MODULE,
	573	.act = tcf_csum,
	574	.dump = tcf_csum_dump,
	575	.cleanup = tcf_csum_cleanup,
	576	.lookup = tcf_hash_search,
	577	.init = tcf_csum_init,
	578	.walk = tcf_generic_walker
eb4d4065 GB	579	};
	580
	581	MODULE_DESCRIPTION("Checksum updating actions");
	582	MODULE_LICENSE("GPL");
	583
	584	static int __init csum_init_module(void)
	585	{
	586	return tcf_register_action(&act_csum_ops);
	587	}
	588
	589	static void __exit csum_cleanup_module(void)
	590	{
	591	tcf_unregister_action(&act_csum_ops);
	592	}
	593
	594	module_init(csum_init_module);
	595	module_exit(csum_cleanup_module);