[linux.git] / net / ipv4 / inet_lro.c

/*
 *  linux/net/ipv4/inet_lro.c
 *
 *  Large Receive Offload (ipv4 / tcp)
 *
 *  (C) Copyright IBM Corp. 2007
 *
 *  Authors:
 *       Jan-Bernd Themann <[email protected]>
 *       Christoph Raisch <[email protected]>
 *
 *
 * 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, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


#include <linux/module.h>
#include <linux/if_vlan.h>
#include <linux/inet_lro.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jan-Bernd Themann <[email protected]>");
MODULE_DESCRIPTION("Large Receive Offload (ipv4 / tcp)");

#define TCP_HDR_LEN(tcph) (tcph->doff << 2)
#define IP_HDR_LEN(iph) (iph->ihl << 2)
#define TCP_PAYLOAD_LENGTH(iph, tcph) \
	(ntohs(iph->tot_len) - IP_HDR_LEN(iph) - TCP_HDR_LEN(tcph))

#define IPH_LEN_WO_OPTIONS 5
#define TCPH_LEN_WO_OPTIONS 5
#define TCPH_LEN_W_TIMESTAMP 8

#define LRO_MAX_PG_HLEN 64

#define LRO_INC_STATS(lro_mgr, attr) { lro_mgr->stats.attr++; }

/*
 * Basic tcp checks whether packet is suitable for LRO
 */

static int lro_tcp_ip_check(const struct iphdr *iph, const struct tcphdr *tcph,
			    int len, const struct net_lro_desc *lro_desc)
{
        /* check ip header: don't aggregate padded frames */
	if (ntohs(iph->tot_len) != len)
		return -1;

	if (TCP_PAYLOAD_LENGTH(iph, tcph) == 0)
		return -1;

	if (iph->ihl != IPH_LEN_WO_OPTIONS)
		return -1;

	if (tcph->cwr || tcph->ece || tcph->urg || !tcph->ack ||
	    tcph->rst || tcph->syn || tcph->fin)
		return -1;

	if (INET_ECN_is_ce(ipv4_get_dsfield(iph)))
		return -1;

	if (tcph->doff != TCPH_LEN_WO_OPTIONS &&
	    tcph->doff != TCPH_LEN_W_TIMESTAMP)
		return -1;

	/* check tcp options (only timestamp allowed) */
	if (tcph->doff == TCPH_LEN_W_TIMESTAMP) {
		__be32 *topt = (__be32 *)(tcph + 1);

		if (*topt != htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16)
				   | (TCPOPT_TIMESTAMP << 8)
				   | TCPOLEN_TIMESTAMP))
			return -1;

		/* timestamp should be in right order */
		topt++;
		if (lro_desc && after(ntohl(lro_desc->tcp_rcv_tsval),
				      ntohl(*topt)))
			return -1;

		/* timestamp reply should not be zero */
		topt++;
		if (*topt == 0)
			return -1;
	}

	return 0;
}

static void lro_update_tcp_ip_header(struct net_lro_desc *lro_desc)
{
	struct iphdr *iph = lro_desc->iph;
	struct tcphdr *tcph = lro_desc->tcph;
	__be32 *p;
	__wsum tcp_hdr_csum;

	tcph->ack_seq = lro_desc->tcp_ack;
	tcph->window = lro_desc->tcp_window;

	if (lro_desc->tcp_saw_tstamp) {
		p = (__be32 *)(tcph + 1);
		*(p+2) = lro_desc->tcp_rcv_tsecr;
	}

	iph->tot_len = htons(lro_desc->ip_tot_len);

	iph->check = 0;
	iph->check = ip_fast_csum((u8 *)lro_desc->iph, iph->ihl);

	tcph->check = 0;
	tcp_hdr_csum = csum_partial(tcph, TCP_HDR_LEN(tcph), 0);
	lro_desc->data_csum = csum_add(lro_desc->data_csum, tcp_hdr_csum);
	tcph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
					lro_desc->ip_tot_len -
					IP_HDR_LEN(iph), IPPROTO_TCP,
					lro_desc->data_csum);
}

static __wsum lro_tcp_data_csum(struct iphdr *iph, struct tcphdr *tcph, int len)
{
	__wsum tcp_csum;
	__wsum tcp_hdr_csum;
	__wsum tcp_ps_hdr_csum;

	tcp_csum = ~csum_unfold(tcph->check);
	tcp_hdr_csum = csum_partial(tcph, TCP_HDR_LEN(tcph), tcp_csum);

	tcp_ps_hdr_csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
					     len + TCP_HDR_LEN(tcph),
					     IPPROTO_TCP, 0);

	return csum_sub(csum_sub(tcp_csum, tcp_hdr_csum),
			tcp_ps_hdr_csum);
}

static void lro_init_desc(struct net_lro_desc *lro_desc, struct sk_buff *skb,
			  struct iphdr *iph, struct tcphdr *tcph)
{
	int nr_frags;
	__be32 *ptr;
	u32 tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);

	nr_frags = skb_shinfo(skb)->nr_frags;
	lro_desc->parent = skb;
	lro_desc->next_frag = &(skb_shinfo(skb)->frags[nr_frags]);
	lro_desc->iph = iph;
	lro_desc->tcph = tcph;
	lro_desc->tcp_next_seq = ntohl(tcph->seq) + tcp_data_len;
	lro_desc->tcp_ack = tcph->ack_seq;
	lro_desc->tcp_window = tcph->window;

	lro_desc->pkt_aggr_cnt = 1;
	lro_desc->ip_tot_len = ntohs(iph->tot_len);

	if (tcph->doff == 8) {
		ptr = (__be32 *)(tcph+1);
		lro_desc->tcp_saw_tstamp = 1;
		lro_desc->tcp_rcv_tsval = *(ptr+1);
		lro_desc->tcp_rcv_tsecr = *(ptr+2);
	}

	lro_desc->mss = tcp_data_len;
	lro_desc->active = 1;

	lro_desc->data_csum = lro_tcp_data_csum(iph, tcph,
						tcp_data_len);
}

static inline void lro_clear_desc(struct net_lro_desc *lro_desc)
{
	memset(lro_desc, 0, sizeof(struct net_lro_desc));
}

static void lro_add_common(struct net_lro_desc *lro_desc, struct iphdr *iph,
			   struct tcphdr *tcph, int tcp_data_len)
{
	struct sk_buff *parent = lro_desc->parent;
	__be32 *topt;

	lro_desc->pkt_aggr_cnt++;
	lro_desc->ip_tot_len += tcp_data_len;
	lro_desc->tcp_next_seq += tcp_data_len;
	lro_desc->tcp_window = tcph->window;
	lro_desc->tcp_ack = tcph->ack_seq;

	/* don't update tcp_rcv_tsval, would not work with PAWS */
	if (lro_desc->tcp_saw_tstamp) {
		topt = (__be32 *) (tcph + 1);
		lro_desc->tcp_rcv_tsecr = *(topt + 2);
	}

	lro_desc->data_csum = csum_block_add(lro_desc->data_csum,
					     lro_tcp_data_csum(iph, tcph,
							       tcp_data_len),
					     parent->len);

	parent->len += tcp_data_len;
	parent->data_len += tcp_data_len;
	if (tcp_data_len > lro_desc->mss)
		lro_desc->mss = tcp_data_len;
}

static void lro_add_packet(struct net_lro_desc *lro_desc, struct sk_buff *skb,
			   struct iphdr *iph, struct tcphdr *tcph)
{
	struct sk_buff *parent = lro_desc->parent;
	int tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);

	lro_add_common(lro_desc, iph, tcph, tcp_data_len);

	skb_pull(skb, (skb->len - tcp_data_len));
	parent->truesize += skb->truesize;

	if (lro_desc->last_skb)
		lro_desc->last_skb->next = skb;
	else
		skb_shinfo(parent)->frag_list = skb;

	lro_desc->last_skb = skb;
}

static void lro_add_frags(struct net_lro_desc *lro_desc,
			  int len, int hlen, int truesize,
			  struct skb_frag_struct *skb_frags,
			  struct iphdr *iph, struct tcphdr *tcph)
{
	struct sk_buff *skb = lro_desc->parent;
	int tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);

	lro_add_common(lro_desc, iph, tcph, tcp_data_len);

	skb->truesize += truesize;

	skb_frags[0].page_offset += hlen;
	skb_frag_size_sub(&skb_frags[0], hlen);

	while (tcp_data_len > 0) {
		*(lro_desc->next_frag) = *skb_frags;
		tcp_data_len -= skb_frag_size(skb_frags);
		lro_desc->next_frag++;
		skb_frags++;
		skb_shinfo(skb)->nr_frags++;
	}
}

static int lro_check_tcp_conn(struct net_lro_desc *lro_desc,
			      struct iphdr *iph,
			      struct tcphdr *tcph)
{
	if ((lro_desc->iph->saddr != iph->saddr) ||
	    (lro_desc->iph->daddr != iph->daddr) ||
	    (lro_desc->tcph->source != tcph->source) ||
	    (lro_desc->tcph->dest != tcph->dest))
		return -1;
	return 0;
}

static struct net_lro_desc *lro_get_desc(struct net_lro_mgr *lro_mgr,
					 struct net_lro_desc *lro_arr,
					 struct iphdr *iph,
					 struct tcphdr *tcph)
{
	struct net_lro_desc *lro_desc = NULL;
	struct net_lro_desc *tmp;
	int max_desc = lro_mgr->max_desc;
	int i;

	for (i = 0; i < max_desc; i++) {
		tmp = &lro_arr[i];
		if (tmp->active)
			if (!lro_check_tcp_conn(tmp, iph, tcph)) {
				lro_desc = tmp;
				goto out;
			}
	}

	for (i = 0; i < max_desc; i++) {
		if (!lro_arr[i].active) {
			lro_desc = &lro_arr[i];
			goto out;
		}
	}

	LRO_INC_STATS(lro_mgr, no_desc);
out:
	return lro_desc;
}

static void lro_flush(struct net_lro_mgr *lro_mgr,
		      struct net_lro_desc *lro_desc)
{
	if (lro_desc->pkt_aggr_cnt > 1)
		lro_update_tcp_ip_header(lro_desc);

	skb_shinfo(lro_desc->parent)->gso_size = lro_desc->mss;

	if (lro_mgr->features & LRO_F_NAPI)
		netif_receive_skb(lro_desc->parent);
	else
		netif_rx(lro_desc->parent);

	LRO_INC_STATS(lro_mgr, flushed);
	lro_clear_desc(lro_desc);
}

static int __lro_proc_skb(struct net_lro_mgr *lro_mgr, struct sk_buff *skb,
			  void *priv)
{
	struct net_lro_desc *lro_desc;
	struct iphdr *iph;
	struct tcphdr *tcph;
	u64 flags;
	int vlan_hdr_len = 0;

	if (!lro_mgr->get_skb_header ||
	    lro_mgr->get_skb_header(skb, (void *)&iph, (void *)&tcph,
				    &flags, priv))
		goto out;

	if (!(flags & LRO_IPV4) || !(flags & LRO_TCP))
		goto out;

	lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
	if (!lro_desc)
		goto out;

	if ((skb->protocol == htons(ETH_P_8021Q)) &&
	    !(lro_mgr->features & LRO_F_EXTRACT_VLAN_ID))
		vlan_hdr_len = VLAN_HLEN;

	if (!lro_desc->active) { /* start new lro session */
		if (lro_tcp_ip_check(iph, tcph, skb->len - vlan_hdr_len, NULL))
			goto out;

		skb->ip_summed = lro_mgr->ip_summed_aggr;
		lro_init_desc(lro_desc, skb, iph, tcph);
		LRO_INC_STATS(lro_mgr, aggregated);
		return 0;
	}

	if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
		goto out2;

	if (lro_tcp_ip_check(iph, tcph, skb->len, lro_desc))
		goto out2;

	lro_add_packet(lro_desc, skb, iph, tcph);
	LRO_INC_STATS(lro_mgr, aggregated);

	if ((lro_desc->pkt_aggr_cnt >= lro_mgr->max_aggr) ||
	    lro_desc->parent->len > (0xFFFF - lro_mgr->dev->mtu))
		lro_flush(lro_mgr, lro_desc);

	return 0;

out2: /* send aggregated SKBs to stack */
	lro_flush(lro_mgr, lro_desc);

out:
	return 1;
}


static struct sk_buff *lro_gen_skb(struct net_lro_mgr *lro_mgr,
				   struct skb_frag_struct *frags,
				   int len, int true_size,
				   void *mac_hdr,
				   int hlen, __wsum sum,
				   u32 ip_summed)
{
	struct sk_buff *skb;
	struct skb_frag_struct *skb_frags;
	int data_len = len;
	int hdr_len = min(len, hlen);

	skb = netdev_alloc_skb(lro_mgr->dev, hlen + lro_mgr->frag_align_pad);
	if (!skb)
		return NULL;

	skb_reserve(skb, lro_mgr->frag_align_pad);
	skb->len = len;
	skb->data_len = len - hdr_len;
	skb->truesize += true_size;
	skb->tail += hdr_len;

	memcpy(skb->data, mac_hdr, hdr_len);

	skb_frags = skb_shinfo(skb)->frags;
	while (data_len > 0) {
		*skb_frags = *frags;
		data_len -= skb_frag_size(frags);
		skb_frags++;
		frags++;
		skb_shinfo(skb)->nr_frags++;
	}

	skb_shinfo(skb)->frags[0].page_offset += hdr_len;
	skb_frag_size_sub(&skb_shinfo(skb)->frags[0], hdr_len);

	skb->ip_summed = ip_summed;
	skb->csum = sum;
	skb->protocol = eth_type_trans(skb, lro_mgr->dev);
	return skb;
}

static struct sk_buff *__lro_proc_segment(struct net_lro_mgr *lro_mgr,
					  struct skb_frag_struct *frags,
					  int len, int true_size,
					  void *priv, __wsum sum)
{
	struct net_lro_desc *lro_desc;
	struct iphdr *iph;
	struct tcphdr *tcph;
	struct sk_buff *skb;
	u64 flags;
	void *mac_hdr;
	int mac_hdr_len;
	int hdr_len = LRO_MAX_PG_HLEN;
	int vlan_hdr_len = 0;

	if (!lro_mgr->get_frag_header ||
	    lro_mgr->get_frag_header(frags, (void *)&mac_hdr, (void *)&iph,
				     (void *)&tcph, &flags, priv)) {
		mac_hdr = skb_frag_address(frags);
		goto out1;
	}

	if (!(flags & LRO_IPV4) || !(flags & LRO_TCP))
		goto out1;

	hdr_len = (int)((void *)(tcph) + TCP_HDR_LEN(tcph) - mac_hdr);
	mac_hdr_len = (int)((void *)(iph) - mac_hdr);

	lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
	if (!lro_desc)
		goto out1;

	if (!lro_desc->active) { /* start new lro session */
		if (lro_tcp_ip_check(iph, tcph, len - mac_hdr_len, NULL))
			goto out1;

		skb = lro_gen_skb(lro_mgr, frags, len, true_size, mac_hdr,
				  hdr_len, 0, lro_mgr->ip_summed_aggr);
		if (!skb)
			goto out;

		if ((skb->protocol == htons(ETH_P_8021Q)) &&
		    !(lro_mgr->features & LRO_F_EXTRACT_VLAN_ID))
			vlan_hdr_len = VLAN_HLEN;

		iph = (void *)(skb->data + vlan_hdr_len);
		tcph = (void *)((u8 *)skb->data + vlan_hdr_len
				+ IP_HDR_LEN(iph));

		lro_init_desc(lro_desc, skb, iph, tcph);
		LRO_INC_STATS(lro_mgr, aggregated);
		return NULL;
	}

	if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
		goto out2;

	if (lro_tcp_ip_check(iph, tcph, len - mac_hdr_len, lro_desc))
		goto out2;

	lro_add_frags(lro_desc, len, hdr_len, true_size, frags, iph, tcph);
	LRO_INC_STATS(lro_mgr, aggregated);

	if ((skb_shinfo(lro_desc->parent)->nr_frags >= lro_mgr->max_aggr) ||
	    lro_desc->parent->len > (0xFFFF - lro_mgr->dev->mtu))
		lro_flush(lro_mgr, lro_desc);

	return NULL;

out2: /* send aggregated packets to the stack */
	lro_flush(lro_mgr, lro_desc);

out1:  /* Original packet has to be posted to the stack */
	skb = lro_gen_skb(lro_mgr, frags, len, true_size, mac_hdr,
			  hdr_len, sum, lro_mgr->ip_summed);
out:
	return skb;
}

void lro_receive_skb(struct net_lro_mgr *lro_mgr,
		     struct sk_buff *skb,
		     void *priv)
{
	if (__lro_proc_skb(lro_mgr, skb, priv)) {
		if (lro_mgr->features & LRO_F_NAPI)
			netif_receive_skb(skb);
		else
			netif_rx(skb);
	}
}
EXPORT_SYMBOL(lro_receive_skb);

void lro_receive_frags(struct net_lro_mgr *lro_mgr,
		       struct skb_frag_struct *frags,
		       int len, int true_size, void *priv, __wsum sum)
{
	struct sk_buff *skb;

	skb = __lro_proc_segment(lro_mgr, frags, len, true_size, priv, sum);
	if (!skb)
		return;

	if (lro_mgr->features & LRO_F_NAPI)
		netif_receive_skb(skb);
	else
		netif_rx(skb);
}
EXPORT_SYMBOL(lro_receive_frags);

void lro_flush_all(struct net_lro_mgr *lro_mgr)
{
	int i;
	struct net_lro_desc *lro_desc = lro_mgr->lro_arr;

	for (i = 0; i < lro_mgr->max_desc; i++) {
		if (lro_desc[i].active)
			lro_flush(lro_mgr, &lro_desc[i]);
	}
}
EXPORT_SYMBOL(lro_flush_all);

void lro_flush_pkt(struct net_lro_mgr *lro_mgr,
		  struct iphdr *iph, struct tcphdr *tcph)
{
	struct net_lro_desc *lro_desc;

	lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
	if (lro_desc->active)
		lro_flush(lro_mgr, lro_desc);
}
EXPORT_SYMBOL(lro_flush_pkt);
Commit	Line	Data
71c87e0c JBT	1	/*
	2	* linux/net/ipv4/inet_lro.c
	3	*
	4	* Large Receive Offload (ipv4 / tcp)
	5	*
	6	* (C) Copyright IBM Corp. 2007
	7	*
	8	* Authors:
	9	* Jan-Bernd Themann <[email protected]>
	10	* Christoph Raisch <[email protected]>
	11	*
	12	*
	13	* This program is free software; you can redistribute it and/or modify
	14	* it under the terms of the GNU General Public License as published by
	15	* the Free Software Foundation; either version 2, or (at your option)
	16	* any later version.
	17	*
	18	* This program is distributed in the hope that it will be useful,
	19	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	20	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	21	* GNU General Public License for more details.
	22	*
	23	* You should have received a copy of the GNU General Public License
	24	* along with this program; if not, write to the Free Software
	25	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	26	*/
	27
	28
	29	#include <linux/module.h>
	30	#include <linux/if_vlan.h>
	31	#include <linux/inet_lro.h>
	32
	33	MODULE_LICENSE("GPL");
	34	MODULE_AUTHOR("Jan-Bernd Themann <[email protected]>");
	35	MODULE_DESCRIPTION("Large Receive Offload (ipv4 / tcp)");
	36
	37	#define TCP_HDR_LEN(tcph) (tcph->doff << 2)
	38	#define IP_HDR_LEN(iph) (iph->ihl << 2)
	39	#define TCP_PAYLOAD_LENGTH(iph, tcph) \
	40	(ntohs(iph->tot_len) - IP_HDR_LEN(iph) - TCP_HDR_LEN(tcph))
	41
	42	#define IPH_LEN_WO_OPTIONS 5
	43	#define TCPH_LEN_WO_OPTIONS 5
	44	#define TCPH_LEN_W_TIMESTAMP 8
	45
	46	#define LRO_MAX_PG_HLEN 64
	47
	48	#define LRO_INC_STATS(lro_mgr, attr) { lro_mgr->stats.attr++; }
	49
	50	/*
	51	* Basic tcp checks whether packet is suitable for LRO
	52	*/
	53
b71d1d42 ED	54	static int lro_tcp_ip_check(const struct iphdr iph, const struct tcphdr tcph,
b71d1d42 ED	55	int len, const struct net_lro_desc *lro_desc)
71c87e0c JBT	56	{
	57	/* check ip header: don't aggregate padded frames */
	58	if (ntohs(iph->tot_len) != len)
	59	return -1;
	60
	61	if (TCP_PAYLOAD_LENGTH(iph, tcph) == 0)
	62	return -1;
	63
	64	if (iph->ihl != IPH_LEN_WO_OPTIONS)
	65	return -1;
	66
9d4fb27d JP	67	if (tcph->cwr \|\| tcph->ece \|\| tcph->urg \|\| !tcph->ack \|\|
9d4fb27d JP	68	tcph->rst \|\| tcph->syn \|\| tcph->fin)
71c87e0c JBT	69	return -1;
	70
	71	if (INET_ECN_is_ce(ipv4_get_dsfield(iph)))
	72	return -1;
	73
9d4fb27d JP	74	if (tcph->doff != TCPH_LEN_WO_OPTIONS &&
9d4fb27d JP	75	tcph->doff != TCPH_LEN_W_TIMESTAMP)
71c87e0c JBT	76	return -1;
	77
	78	/* check tcp options (only timestamp allowed) */
	79	if (tcph->doff == TCPH_LEN_W_TIMESTAMP) {
9df7c98a	80	__be32 topt = (__be32 )(tcph + 1);
71c87e0c JBT	81
	82	if (*topt != htonl((TCPOPT_NOP << 24) \| (TCPOPT_NOP << 16)
	83	\| (TCPOPT_TIMESTAMP << 8)
	84	\| TCPOLEN_TIMESTAMP))
	85	return -1;
	86
	87	/* timestamp should be in right order */
	88	topt++;
	89	if (lro_desc && after(ntohl(lro_desc->tcp_rcv_tsval),
	90	ntohl(*topt)))
	91	return -1;
	92
	93	/* timestamp reply should not be zero */
	94	topt++;
	95	if (*topt == 0)
	96	return -1;
	97	}
	98
	99	return 0;
	100	}
	101
	102	static void lro_update_tcp_ip_header(struct net_lro_desc *lro_desc)
	103	{
	104	struct iphdr *iph = lro_desc->iph;
	105	struct tcphdr *tcph = lro_desc->tcph;
9df7c98a	106	__be32 *p;
71c87e0c JBT	107	__wsum tcp_hdr_csum;
	108
	109	tcph->ack_seq = lro_desc->tcp_ack;
	110	tcph->window = lro_desc->tcp_window;
	111
	112	if (lro_desc->tcp_saw_tstamp) {
9df7c98a	113	p = (__be32 *)(tcph + 1);
71c87e0c JBT	114	*(p+2) = lro_desc->tcp_rcv_tsecr;
	115	}
	116
	117	iph->tot_len = htons(lro_desc->ip_tot_len);
	118
	119	iph->check = 0;
	120	iph->check = ip_fast_csum((u8 *)lro_desc->iph, iph->ihl);
	121
	122	tcph->check = 0;
07f0757a	123	tcp_hdr_csum = csum_partial(tcph, TCP_HDR_LEN(tcph), 0);
71c87e0c JBT	124	lro_desc->data_csum = csum_add(lro_desc->data_csum, tcp_hdr_csum);
	125	tcph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
	126	lro_desc->ip_tot_len -
	127	IP_HDR_LEN(iph), IPPROTO_TCP,
	128	lro_desc->data_csum);
	129	}
	130
	131	static __wsum lro_tcp_data_csum(struct iphdr iph, struct tcphdr tcph, int len)
	132	{
	133	__wsum tcp_csum;
	134	__wsum tcp_hdr_csum;
	135	__wsum tcp_ps_hdr_csum;
	136
	137	tcp_csum = ~csum_unfold(tcph->check);
07f0757a	138	tcp_hdr_csum = csum_partial(tcph, TCP_HDR_LEN(tcph), tcp_csum);
71c87e0c JBT	139
	140	tcp_ps_hdr_csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
	141	len + TCP_HDR_LEN(tcph),
	142	IPPROTO_TCP, 0);
	143
	144	return csum_sub(csum_sub(tcp_csum, tcp_hdr_csum),
	145	tcp_ps_hdr_csum);
	146	}
	147
	148	static void lro_init_desc(struct net_lro_desc lro_desc, struct sk_buff skb,
9fea0330	149	struct iphdr iph, struct tcphdr tcph)
71c87e0c JBT	150	{
71c87e0c JBT	151	int nr_frags;
9df7c98a	152	__be32 *ptr;
71c87e0c JBT	153	u32 tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
	154
	155	nr_frags = skb_shinfo(skb)->nr_frags;
	156	lro_desc->parent = skb;
	157	lro_desc->next_frag = &(skb_shinfo(skb)->frags[nr_frags]);
	158	lro_desc->iph = iph;
	159	lro_desc->tcph = tcph;
	160	lro_desc->tcp_next_seq = ntohl(tcph->seq) + tcp_data_len;
f53f4137	161	lro_desc->tcp_ack = tcph->ack_seq;
71c87e0c JBT	162	lro_desc->tcp_window = tcph->window;
	163
	164	lro_desc->pkt_aggr_cnt = 1;
	165	lro_desc->ip_tot_len = ntohs(iph->tot_len);
	166
	167	if (tcph->doff == 8) {
9df7c98a	168	ptr = (__be32 *)(tcph+1);
71c87e0c JBT	169	lro_desc->tcp_saw_tstamp = 1;
	170	lro_desc->tcp_rcv_tsval = *(ptr+1);
	171	lro_desc->tcp_rcv_tsecr = *(ptr+2);
	172	}
	173
	174	lro_desc->mss = tcp_data_len;
71c87e0c JBT	175	lro_desc->active = 1;
	176
	177	lro_desc->data_csum = lro_tcp_data_csum(iph, tcph,
	178	tcp_data_len);
	179	}
	180
	181	static inline void lro_clear_desc(struct net_lro_desc *lro_desc)
	182	{
	183	memset(lro_desc, 0, sizeof(struct net_lro_desc));
	184	}
	185
	186	static void lro_add_common(struct net_lro_desc lro_desc, struct iphdr iph,
	187	struct tcphdr *tcph, int tcp_data_len)
	188	{
	189	struct sk_buff *parent = lro_desc->parent;
9df7c98a	190	__be32 *topt;
71c87e0c JBT	191
	192	lro_desc->pkt_aggr_cnt++;
	193	lro_desc->ip_tot_len += tcp_data_len;
	194	lro_desc->tcp_next_seq += tcp_data_len;
	195	lro_desc->tcp_window = tcph->window;
	196	lro_desc->tcp_ack = tcph->ack_seq;
	197
	198	/* don't update tcp_rcv_tsval, would not work with PAWS */
	199	if (lro_desc->tcp_saw_tstamp) {
9df7c98a	200	topt = (__be32 *) (tcph + 1);
71c87e0c JBT	201	lro_desc->tcp_rcv_tsecr = *(topt + 2);
	202	}
	203
	204	lro_desc->data_csum = csum_block_add(lro_desc->data_csum,
	205	lro_tcp_data_csum(iph, tcph,
	206	tcp_data_len),
	207	parent->len);
	208
	209	parent->len += tcp_data_len;
	210	parent->data_len += tcp_data_len;
	211	if (tcp_data_len > lro_desc->mss)
	212	lro_desc->mss = tcp_data_len;
	213	}
	214
	215	static void lro_add_packet(struct net_lro_desc lro_desc, struct sk_buff skb,
	216	struct iphdr iph, struct tcphdr tcph)
	217	{
	218	struct sk_buff *parent = lro_desc->parent;
	219	int tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
	220
	221	lro_add_common(lro_desc, iph, tcph, tcp_data_len);
	222
	223	skb_pull(skb, (skb->len - tcp_data_len));
	224	parent->truesize += skb->truesize;
	225
	226	if (lro_desc->last_skb)
	227	lro_desc->last_skb->next = skb;
	228	else
	229	skb_shinfo(parent)->frag_list = skb;
	230
	231	lro_desc->last_skb = skb;
	232	}
	233
	234	static void lro_add_frags(struct net_lro_desc *lro_desc,
	235	int len, int hlen, int truesize,
	236	struct skb_frag_struct *skb_frags,
	237	struct iphdr iph, struct tcphdr tcph)
	238	{
	239	struct sk_buff *skb = lro_desc->parent;
	240	int tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
	241
	242	lro_add_common(lro_desc, iph, tcph, tcp_data_len);
	243
	244	skb->truesize += truesize;
	245
	246	skb_frags[0].page_offset += hlen;
9e903e08	247	skb_frag_size_sub(&skb_frags[0], hlen);
71c87e0c JBT	248
	249	while (tcp_data_len > 0) {
	250	(lro_desc->next_frag) = skb_frags;
9e903e08	251	tcp_data_len -= skb_frag_size(skb_frags);
71c87e0c JBT	252	lro_desc->next_frag++;
	253	skb_frags++;
	254	skb_shinfo(skb)->nr_frags++;
	255	}
	256	}
	257
	258	static int lro_check_tcp_conn(struct net_lro_desc *lro_desc,
	259	struct iphdr *iph,
	260	struct tcphdr *tcph)
	261	{
9d4fb27d JP	262	if ((lro_desc->iph->saddr != iph->saddr) \|\|
	263	(lro_desc->iph->daddr != iph->daddr) \|\|
	264	(lro_desc->tcph->source != tcph->source) \|\|
	265	(lro_desc->tcph->dest != tcph->dest))
71c87e0c JBT	266	return -1;
	267	return 0;
	268	}
	269
	270	static struct net_lro_desc lro_get_desc(struct net_lro_mgr lro_mgr,
	271	struct net_lro_desc *lro_arr,
	272	struct iphdr *iph,
	273	struct tcphdr *tcph)
	274	{
	275	struct net_lro_desc *lro_desc = NULL;
	276	struct net_lro_desc *tmp;
	277	int max_desc = lro_mgr->max_desc;
	278	int i;
	279
	280	for (i = 0; i < max_desc; i++) {
	281	tmp = &lro_arr[i];
	282	if (tmp->active)
	283	if (!lro_check_tcp_conn(tmp, iph, tcph)) {
	284	lro_desc = tmp;
	285	goto out;
	286	}
	287	}
	288
	289	for (i = 0; i < max_desc; i++) {
	290	if (!lro_arr[i].active) {
	291	lro_desc = &lro_arr[i];
	292	goto out;
	293	}
	294	}
	295
	296	LRO_INC_STATS(lro_mgr, no_desc);
	297	out:
	298	return lro_desc;
	299	}
	300
	301	static void lro_flush(struct net_lro_mgr *lro_mgr,
	302	struct net_lro_desc *lro_desc)
	303	{
	304	if (lro_desc->pkt_aggr_cnt > 1)
	305	lro_update_tcp_ip_header(lro_desc);
	306
	307	skb_shinfo(lro_desc->parent)->gso_size = lro_desc->mss;
	308
9fea0330 JP	309	if (lro_mgr->features & LRO_F_NAPI)
	310	netif_receive_skb(lro_desc->parent);
	311	else
	312	netif_rx(lro_desc->parent);
71c87e0c JBT	313
	314	LRO_INC_STATS(lro_mgr, flushed);
	315	lro_clear_desc(lro_desc);
	316	}
	317
	318	static int __lro_proc_skb(struct net_lro_mgr lro_mgr, struct sk_buff skb,
9fea0330	319	void *priv)
71c87e0c JBT	320	{
	321	struct net_lro_desc *lro_desc;
	322	struct iphdr *iph;
	323	struct tcphdr *tcph;
	324	u64 flags;
	325	int vlan_hdr_len = 0;
	326
9d4fb27d JP	327	if (!lro_mgr->get_skb_header \|\|
	328	lro_mgr->get_skb_header(skb, (void )&iph, (void )&tcph,
	329	&flags, priv))
71c87e0c JBT	330	goto out;
	331
	332	if (!(flags & LRO_IPV4) \|\| !(flags & LRO_TCP))
	333	goto out;
	334
	335	lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
	336	if (!lro_desc)
	337	goto out;
	338
9d4fb27d JP	339	if ((skb->protocol == htons(ETH_P_8021Q)) &&
9d4fb27d JP	340	!(lro_mgr->features & LRO_F_EXTRACT_VLAN_ID))
71c87e0c JBT	341	vlan_hdr_len = VLAN_HLEN;
	342
	343	if (!lro_desc->active) { /* start new lro session */
	344	if (lro_tcp_ip_check(iph, tcph, skb->len - vlan_hdr_len, NULL))
	345	goto out;
	346
	347	skb->ip_summed = lro_mgr->ip_summed_aggr;
9fea0330	348	lro_init_desc(lro_desc, skb, iph, tcph);
71c87e0c JBT	349	LRO_INC_STATS(lro_mgr, aggregated);
	350	return 0;
	351	}
	352
	353	if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
	354	goto out2;
	355
	356	if (lro_tcp_ip_check(iph, tcph, skb->len, lro_desc))
	357	goto out2;
	358
	359	lro_add_packet(lro_desc, skb, iph, tcph);
	360	LRO_INC_STATS(lro_mgr, aggregated);
	361
	362	if ((lro_desc->pkt_aggr_cnt >= lro_mgr->max_aggr) \|\|
	363	lro_desc->parent->len > (0xFFFF - lro_mgr->dev->mtu))
	364	lro_flush(lro_mgr, lro_desc);
	365
	366	return 0;
	367
	368	out2: /* send aggregated SKBs to stack */
	369	lro_flush(lro_mgr, lro_desc);
	370
251a4b32	371	out:
71c87e0c JBT	372	return 1;
	373	}
	374
	375
	376	static struct sk_buff lro_gen_skb(struct net_lro_mgr lro_mgr,
	377	struct skb_frag_struct *frags,
	378	int len, int true_size,
	379	void *mac_hdr,
	380	int hlen, __wsum sum,
	381	u32 ip_summed)
	382	{
	383	struct sk_buff *skb;
	384	struct skb_frag_struct *skb_frags;
	385	int data_len = len;
	386	int hdr_len = min(len, hlen);
	387
621544eb	388	skb = netdev_alloc_skb(lro_mgr->dev, hlen + lro_mgr->frag_align_pad);
71c87e0c JBT	389	if (!skb)
	390	return NULL;
	391
621544eb	392	skb_reserve(skb, lro_mgr->frag_align_pad);
71c87e0c JBT	393	skb->len = len;
	394	skb->data_len = len - hdr_len;
	395	skb->truesize += true_size;
	396	skb->tail += hdr_len;
	397
	398	memcpy(skb->data, mac_hdr, hdr_len);
	399
	400	skb_frags = skb_shinfo(skb)->frags;
	401	while (data_len > 0) {
	402	skb_frags = frags;
9e903e08	403	data_len -= skb_frag_size(frags);
71c87e0c JBT	404	skb_frags++;
	405	frags++;
	406	skb_shinfo(skb)->nr_frags++;
	407	}
	408
	409	skb_shinfo(skb)->frags[0].page_offset += hdr_len;
9e903e08	410	skb_frag_size_sub(&skb_shinfo(skb)->frags[0], hdr_len);
71c87e0c JBT	411
	412	skb->ip_summed = ip_summed;
	413	skb->csum = sum;
	414	skb->protocol = eth_type_trans(skb, lro_mgr->dev);
	415	return skb;
	416	}
	417
	418	static struct sk_buff __lro_proc_segment(struct net_lro_mgr lro_mgr,
	419	struct skb_frag_struct *frags,
	420	int len, int true_size,
9fea0330	421	void *priv, __wsum sum)
71c87e0c JBT	422	{
	423	struct net_lro_desc *lro_desc;
	424	struct iphdr *iph;
	425	struct tcphdr *tcph;
	426	struct sk_buff *skb;
	427	u64 flags;
	428	void *mac_hdr;
	429	int mac_hdr_len;
	430	int hdr_len = LRO_MAX_PG_HLEN;
	431	int vlan_hdr_len = 0;
	432
9d4fb27d JP	433	if (!lro_mgr->get_frag_header \|\|
	434	lro_mgr->get_frag_header(frags, (void )&mac_hdr, (void )&iph,
	435	(void *)&tcph, &flags, priv)) {
aff65da0	436	mac_hdr = skb_frag_address(frags);
71c87e0c JBT	437	goto out1;
	438	}
	439
	440	if (!(flags & LRO_IPV4) \|\| !(flags & LRO_TCP))
	441	goto out1;
	442
	443	hdr_len = (int)((void *)(tcph) + TCP_HDR_LEN(tcph) - mac_hdr);
	444	mac_hdr_len = (int)((void *)(iph) - mac_hdr);
	445
	446	lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
	447	if (!lro_desc)
	448	goto out1;
	449
	450	if (!lro_desc->active) { /* start new lro session */
	451	if (lro_tcp_ip_check(iph, tcph, len - mac_hdr_len, NULL))
	452	goto out1;
	453
	454	skb = lro_gen_skb(lro_mgr, frags, len, true_size, mac_hdr,
	455	hdr_len, 0, lro_mgr->ip_summed_aggr);
	456	if (!skb)
	457	goto out;
	458
9d4fb27d JP	459	if ((skb->protocol == htons(ETH_P_8021Q)) &&
9d4fb27d JP	460	!(lro_mgr->features & LRO_F_EXTRACT_VLAN_ID))
71c87e0c JBT	461	vlan_hdr_len = VLAN_HLEN;
	462
	463	iph = (void *)(skb->data + vlan_hdr_len);
	464	tcph = (void )((u8 )skb->data + vlan_hdr_len
	465	+ IP_HDR_LEN(iph));
	466
9fea0330	467	lro_init_desc(lro_desc, skb, iph, tcph);
71c87e0c	468	LRO_INC_STATS(lro_mgr, aggregated);
cfcabdcc	469	return NULL;
71c87e0c JBT	470	}
	471
	472	if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
	473	goto out2;
	474
	475	if (lro_tcp_ip_check(iph, tcph, len - mac_hdr_len, lro_desc))
	476	goto out2;
	477
	478	lro_add_frags(lro_desc, len, hdr_len, true_size, frags, iph, tcph);
	479	LRO_INC_STATS(lro_mgr, aggregated);
	480
	481	if ((skb_shinfo(lro_desc->parent)->nr_frags >= lro_mgr->max_aggr) \|\|
	482	lro_desc->parent->len > (0xFFFF - lro_mgr->dev->mtu))
	483	lro_flush(lro_mgr, lro_desc);
	484
	485	return NULL;
	486
	487	out2: /* send aggregated packets to the stack */
	488	lro_flush(lro_mgr, lro_desc);
	489
	490	out1: /* Original packet has to be posted to the stack */
	491	skb = lro_gen_skb(lro_mgr, frags, len, true_size, mac_hdr,
	492	hdr_len, sum, lro_mgr->ip_summed);
	493	out:
	494	return skb;
	495	}
	496
	497	void lro_receive_skb(struct net_lro_mgr *lro_mgr,
	498	struct sk_buff *skb,
	499	void *priv)
	500	{
9fea0330	501	if (__lro_proc_skb(lro_mgr, skb, priv)) {
877364e6	502	if (lro_mgr->features & LRO_F_NAPI)
71c87e0c JBT	503	netif_receive_skb(skb);
	504	else
	505	netif_rx(skb);
	506	}
	507	}
	508	EXPORT_SYMBOL(lro_receive_skb);
	509
71c87e0c JBT	510	void lro_receive_frags(struct net_lro_mgr *lro_mgr,
	511	struct skb_frag_struct *frags,
	512	int len, int true_size, void *priv, __wsum sum)
	513	{
	514	struct sk_buff *skb;
	515
9fea0330	516	skb = __lro_proc_segment(lro_mgr, frags, len, true_size, priv, sum);
71c87e0c JBT	517	if (!skb)
	518	return;
	519
877364e6	520	if (lro_mgr->features & LRO_F_NAPI)
71c87e0c JBT	521	netif_receive_skb(skb);
	522	else
	523	netif_rx(skb);
	524	}
	525	EXPORT_SYMBOL(lro_receive_frags);
	526
71c87e0c JBT	527	void lro_flush_all(struct net_lro_mgr *lro_mgr)
	528	{
	529	int i;
	530	struct net_lro_desc *lro_desc = lro_mgr->lro_arr;
	531
	532	for (i = 0; i < lro_mgr->max_desc; i++) {
	533	if (lro_desc[i].active)
	534	lro_flush(lro_mgr, &lro_desc[i]);
	535	}
	536	}
	537	EXPORT_SYMBOL(lro_flush_all);
	538
	539	void lro_flush_pkt(struct net_lro_mgr *lro_mgr,
	540	struct iphdr iph, struct tcphdr tcph)
	541	{
	542	struct net_lro_desc *lro_desc;
	543
	544	lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
	545	if (lro_desc->active)
	546	lro_flush(lro_mgr, lro_desc);
	547	}
	548	EXPORT_SYMBOL(lro_flush_pkt);