[GitHub/mt8127/android_kernel_alcatel_ttab.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/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>
	32
	33	#include <net/act_api.h>
	34
	35	#include <linux/tc_act/tc_csum.h>
	36	#include <net/tc_act/tc_csum.h>
	37
	38	#define CSUM_TAB_MASK 15
	39	static struct tcf_common *tcf_csum_ht[CSUM_TAB_MASK + 1];
	40	static u32 csum_idx_gen;
	41	static DEFINE_RWLOCK(csum_lock);
	42
	43	static struct tcf_hashinfo csum_hash_info = {
	44	.htab = tcf_csum_ht,
	45	.hmask = CSUM_TAB_MASK,
	46	.lock = &csum_lock,
	47	};
	48
	49	static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
	50	[TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
	51	};
	52
	53	static int tcf_csum_init(struct nlattr nla, struct nlattr est,
	54	struct tc_action *a, int ovr, int bind)
	55	{
	56	struct nlattr *tb[TCA_CSUM_MAX + 1];
	57	struct tc_csum *parm;
	58	struct tcf_common *pc;
	59	struct tcf_csum *p;
	60	int ret = 0, err;
	61
	62	if (nla == NULL)
	63	return -EINVAL;
	64
65	err = nla_parse_nested(tb, TCA_CSUM_MAX, nla,csum_policy);
66	if (err < 0)
67	return err;
68
69	if (tb[TCA_CSUM_PARMS] == NULL)
70	return -EINVAL;
71	parm = nla_data(tb[TCA_CSUM_PARMS]);
72
73	pc = tcf_hash_check(parm->index, a, bind, &csum_hash_info);
74	if (!pc) {
75	pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind, &csum_idx_gen, &csum_hash_info);
76	if (IS_ERR(pc))
77	return PTR_ERR(pc);
78	p = to_tcf_csum(pc);
79	ret = ACT_P_CREATED;
80	} else {
81	p = to_tcf_csum(pc);
82	if (!ovr) {
83	tcf_hash_release(pc, bind, &csum_hash_info);
84	return -EEXIST;
85	}
86	}
87
88	spin_lock_bh(&p->tcf_lock);
89	p->tcf_action = parm->action;
90	p->update_flags = parm->update_flags;
91	spin_unlock_bh(&p->tcf_lock);
92
93	if (ret == ACT_P_CREATED)
94	tcf_hash_insert(pc, &csum_hash_info);
95
96	return ret;
97	}
98
99	static int tcf_csum_cleanup(struct tc_action *a, int bind)
100	{
101	struct tcf_csum *p = a->priv;
102	return tcf_hash_release(&p->common, bind, &csum_hash_info);
103	}
104
105	/**
106	* tcf_csum_skb_nextlayer - Get next layer pointer
107	* @skb: sk_buff to use
108	* @ihl: previous summed headers length
109	* @ipl: complete packet length
110	* @jhl: next header length
111	*
112	* Check the expected next layer availability in the specified sk_buff.
113	* Return the next layer pointer if pass, NULL otherwise.
114	*/
115	static void tcf_csum_skb_nextlayer(struct sk_buff skb,
116	unsigned int ihl, unsigned int ipl,
117	unsigned int jhl)
118	{
119	int ntkoff = skb_network_offset(skb);
120	int hl = ihl + jhl;
121
122	if (!pskb_may_pull(skb, ipl + ntkoff) \|\| (ipl < hl) \|\|
123	(skb_cloned(skb) &&
124	!skb_clone_writable(skb, hl + ntkoff) &&
125	pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
126	return NULL;
127	else
128	return (void *)(skb_network_header(skb) + ihl);
129	}
130
131	static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
132	unsigned int ihl, unsigned int ipl)
133	{
134	struct icmphdr *icmph;
135
136	icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
137	if (icmph == NULL)
138	return 0;
139
140	icmph->checksum = 0;
141	skb->csum = csum_partial(icmph, ipl - ihl, 0);
142	icmph->checksum = csum_fold(skb->csum);
143
144	skb->ip_summed = CHECKSUM_NONE;
145
146	return 1;
147	}
148
149	static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
150	unsigned int ihl, unsigned int ipl)
151	{
152	struct igmphdr *igmph;
153
154	igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
155	if (igmph == NULL)
156	return 0;
157
158	igmph->csum = 0;
159	skb->csum = csum_partial(igmph, ipl - ihl, 0);
160	igmph->csum = csum_fold(skb->csum);
161
162	skb->ip_summed = CHECKSUM_NONE;
163
164	return 1;
165	}
166
167	static int tcf_csum_ipv6_icmp(struct sk_buff skb, struct ipv6hdr ip6h,
168	unsigned int ihl, unsigned int ipl)
169	{
170	struct icmp6hdr *icmp6h;
171
172	icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
173	if (icmp6h == NULL)
174	return 0;
175
176	icmp6h->icmp6_cksum = 0;
177	skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
178	icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
179	ipl - ihl, IPPROTO_ICMPV6,
180	skb->csum);
181
182	skb->ip_summed = CHECKSUM_NONE;
183
184	return 1;
185	}
186
187	static int tcf_csum_ipv4_tcp(struct sk_buff skb, struct iphdr iph,
188	unsigned int ihl, unsigned int ipl)
189	{
190	struct tcphdr *tcph;
191
192	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
193	if (tcph == NULL)
194	return 0;
195
196	tcph->check = 0;
197	skb->csum = csum_partial(tcph, ipl - ihl, 0);
198	tcph->check = tcp_v4_check(ipl - ihl,
199	iph->saddr, iph->daddr, skb->csum);
200
201	skb->ip_summed = CHECKSUM_NONE;
202
203	return 1;
204	}
205
206	static int tcf_csum_ipv6_tcp(struct sk_buff skb, struct ipv6hdr ip6h,
207	unsigned int ihl, unsigned int ipl)
208	{
209	struct tcphdr *tcph;
210
211	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
212	if (tcph == NULL)
213	return 0;
214
215	tcph->check = 0;
216	skb->csum = csum_partial(tcph, ipl - ihl, 0);
217	tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
218	ipl - ihl, IPPROTO_TCP,
219	skb->csum);
220
221	skb->ip_summed = CHECKSUM_NONE;
222
223	return 1;
224	}
225
226	static int tcf_csum_ipv4_udp(struct sk_buff skb, struct iphdr iph,
227	unsigned int ihl, unsigned int ipl, int udplite)
228	{
229	struct udphdr *udph;
230	u16 ul;
231
232	/* Support both UDP and UDPLITE checksum algorithms,
233	* Don't use udph->len to get the real length without any protocol check,
234	* UDPLITE uses udph->len for another thing,
235	* Use iph->tot_len, or just ipl.
236	*/
237
238	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
239	if (udph == NULL)
240	return 0;
241
242	ul = ntohs(udph->len);
243
244	if (udplite \|\| udph->check) {
245
246	udph->check = 0;
247
248	if (udplite) {
249	if (ul == 0)
250	skb->csum = csum_partial(udph, ipl - ihl, 0);
251
252	else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
253	skb->csum = csum_partial(udph, ul, 0);
254
255	else
256	goto ignore_obscure_skb;
257	} else {
258	if (ul != ipl - ihl)
259	goto ignore_obscure_skb;
260
261	skb->csum = csum_partial(udph, ul, 0);
262	}
263
264	udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
265	ul, iph->protocol,
266	skb->csum);
267
268	if (!udph->check)
269	udph->check = CSUM_MANGLED_0;
270	}
271
272	skb->ip_summed = CHECKSUM_NONE;
273
274	ignore_obscure_skb:
275	return 1;
276	}
277
278	static int tcf_csum_ipv6_udp(struct sk_buff skb, struct ipv6hdr ip6h,
279	unsigned int ihl, unsigned int ipl, int udplite)
280	{
281	struct udphdr *udph;
282	u16 ul;
283
284	/* Support both UDP and UDPLITE checksum algorithms,
285	* Don't use udph->len to get the real length without any protocol check,
286	* UDPLITE uses udph->len for another thing,
287	* Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
288	*/
289
290	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
291	if (udph == NULL)
292	return 0;
293
294	ul = ntohs(udph->len);
295
296	udph->check = 0;
297
298	if (udplite) {
299	if (ul == 0)
300	skb->csum = csum_partial(udph, ipl - ihl, 0);
301
302	else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
303	skb->csum = csum_partial(udph, ul, 0);
304
305	else
306	goto ignore_obscure_skb;
307	} else {
308	if (ul != ipl - ihl)
309	goto ignore_obscure_skb;
310
311	skb->csum = csum_partial(udph, ul, 0);
312	}
313
314	udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
315	udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
316	skb->csum);
317
318	if (!udph->check)
319	udph->check = CSUM_MANGLED_0;
320
321	skb->ip_summed = CHECKSUM_NONE;
322
323	ignore_obscure_skb:
324	return 1;
325	}
326
327	static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
328	{
329	struct iphdr *iph;
330	int ntkoff;
331
332	ntkoff = skb_network_offset(skb);
333
334	if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
335	goto fail;
336
337	iph = ip_hdr(skb);
338
339	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
340	case IPPROTO_ICMP:
341	if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
342	if (!tcf_csum_ipv4_icmp(skb,
343	iph->ihl * 4, ntohs(iph->tot_len)))
344	goto fail;
345	break;
346	case IPPROTO_IGMP:
347	if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
348	if (!tcf_csum_ipv4_igmp(skb,
349	iph->ihl * 4, ntohs(iph->tot_len)))
350	goto fail;
351	break;
352	case IPPROTO_TCP:
353	if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
354	if (!tcf_csum_ipv4_tcp(skb, iph,
355	iph->ihl * 4, ntohs(iph->tot_len)))
356	goto fail;
357	break;
358	case IPPROTO_UDP:
359	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
360	if (!tcf_csum_ipv4_udp(skb, iph,
361	iph->ihl * 4, ntohs(iph->tot_len), 0))
362	goto fail;
363	break;
364	case IPPROTO_UDPLITE:
365	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
366	if (!tcf_csum_ipv4_udp(skb, iph,
367	iph->ihl * 4, ntohs(iph->tot_len), 1))
368	goto fail;
369	break;
370	}
371
372	if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
373	if (skb_cloned(skb) &&
374	!skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
375	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
376	goto fail;
377
378	ip_send_check(iph);
379	}
380
381	return 1;
382
383	fail:
384	return 0;
385	}
386
387	static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
388	unsigned int ixhl, unsigned int *pl)
389	{
390	int off, len, optlen;
391	unsigned char xh = (void )ip6xh;
392
393	off = sizeof(*ip6xh);
394	len = ixhl - off;
395
396	while (len > 1) {
397	switch (xh[off])
398	{
399	case IPV6_TLV_PAD0:
400	optlen = 1;
401	break;
402	case IPV6_TLV_JUMBO:
403	optlen = xh[off + 1] + 2;
404	if (optlen != 6 \|\| len < 6 \|\| (off & 3) != 2)
405	/* wrong jumbo option length/alignment */
406	return 0;
407	pl = ntohl((__be32 *)(xh + off + 2));
408	goto done;
409	default:
410	optlen = xh[off + 1] + 2;
411	if (optlen > len)
412	/* ignore obscure options */
413	goto done;
414	break;
415	}
416	off += optlen;
417	len -= optlen;
418	}
419
420	done:
421	return 1;
422	}
423
424	static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
425	{
426	struct ipv6hdr *ip6h;
427	struct ipv6_opt_hdr *ip6xh;
428	unsigned int hl, ixhl;
429	unsigned int pl;
430	int ntkoff;
431	u8 nexthdr;
432
433	ntkoff = skb_network_offset(skb);
434
435	hl = sizeof(*ip6h);
436
437	if (!pskb_may_pull(skb, hl + ntkoff))
438	goto fail;
439
440	ip6h = ipv6_hdr(skb);
441
442	pl = ntohs(ip6h->payload_len);
443	nexthdr = ip6h->nexthdr;
444
445	do {
446	switch (nexthdr) {
447	case NEXTHDR_FRAGMENT:
448	goto ignore_skb;
449	case NEXTHDR_ROUTING:
450	case NEXTHDR_HOP:
451	case NEXTHDR_DEST:
452	if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
453	goto fail;
454	ip6xh = (void *)(skb_network_header(skb) + hl);
455	ixhl = ipv6_optlen(ip6xh);
456	if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
457	goto fail;
458	if ((nexthdr == NEXTHDR_HOP) &&
459	!(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
460	goto fail;
461	nexthdr = ip6xh->nexthdr;
462	hl += ixhl;
463	break;
464	case IPPROTO_ICMPV6:
465	if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
466	if (!tcf_csum_ipv6_icmp(skb, ip6h,
467	hl, pl + sizeof(*ip6h)))
468	goto fail;
469	goto done;
470	case IPPROTO_TCP:
471	if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
472	if (!tcf_csum_ipv6_tcp(skb, ip6h,
473	hl, pl + sizeof(*ip6h)))
474	goto fail;
475	goto done;
476	case IPPROTO_UDP:
477	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
478	if (!tcf_csum_ipv6_udp(skb, ip6h,
479	hl, pl + sizeof(*ip6h), 0))
480	goto fail;
481	goto done;
482	case IPPROTO_UDPLITE:
483	if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
484	if (!tcf_csum_ipv6_udp(skb, ip6h,
485	hl, pl + sizeof(*ip6h), 1))
486	goto fail;
487	goto done;
488	default:
489	goto ignore_skb;
490	}
491	} while (pskb_may_pull(skb, hl + 1 + ntkoff));
492
493	done:
494	ignore_skb:
495	return 1;
496
497	fail:
498	return 0;
499	}
500
501	static int tcf_csum(struct sk_buff *skb,
502	struct tc_action a, struct tcf_result res)
503	{
504	struct tcf_csum *p = a->priv;
505	int action;
506	u32 update_flags;
507
508	spin_lock(&p->tcf_lock);
509	p->tcf_tm.lastuse = jiffies;
510	p->tcf_bstats.bytes += qdisc_pkt_len(skb);
511	p->tcf_bstats.packets++;
512	action = p->tcf_action;
513	update_flags = p->update_flags;
514	spin_unlock(&p->tcf_lock);
515
516	if (unlikely(action == TC_ACT_SHOT))
517	goto drop;
518
519	switch (skb->protocol) {
520	case cpu_to_be16(ETH_P_IP):
521	if (!tcf_csum_ipv4(skb, update_flags))
522	goto drop;
523	break;
524	case cpu_to_be16(ETH_P_IPV6):
525	if (!tcf_csum_ipv6(skb, update_flags))
526	goto drop;
527	break;
528	}
529
530	return action;
531
532	drop:
533	spin_lock(&p->tcf_lock);
534	p->tcf_qstats.drops++;
535	spin_unlock(&p->tcf_lock);
536	return TC_ACT_SHOT;
537	}
538
539	static int tcf_csum_dump(struct sk_buff *skb,
540	struct tc_action *a, int bind, int ref)
541	{
542	unsigned char *b = skb_tail_pointer(skb);
543	struct tcf_csum *p = a->priv;
544	struct tc_csum opt = {
545	.update_flags = p->update_flags,
546
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 = {
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
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);