[net-next-2.6.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 <themann@de.ibm.com>
 *       Christoph Raisch <raisch@de.ibm.com>
 *
 *
 * 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 <themann@de.ibm.com>");
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(struct iphdr *iph, struct tcphdr *tcph,
			    int len, 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((u8 *)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((u8 *)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,
			  u16 vlan_tag, struct vlan_group *vgrp)
{
	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->vgrp = vgrp;
	lro_desc->vlan_tag = vlan_tag;
	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_frags[0].size -= hlen;

	while (tcp_data_len > 0) {
		*(lro_desc->next_frag) = *skb_frags;
		tcp_data_len -= skb_frags->size;
		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_desc->vgrp) {
		if (lro_mgr->features & LRO_F_NAPI)
			vlan_hwaccel_receive_skb(lro_desc->parent,
						 lro_desc->vgrp,
						 lro_desc->vlan_tag);
		else
			vlan_hwaccel_rx(lro_desc->parent,
					lro_desc->vgrp,
					lro_desc->vlan_tag);

	} else {
		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,
			  struct vlan_group *vgrp, u16 vlan_tag, 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, vlan_tag, vgrp);
		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:  /* Original SKB has to be posted to stack */
	skb->ip_summed = lro_mgr->ip_summed;
	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 -= frags->size;
		skb_frags++;
		frags++;
		skb_shinfo(skb)->nr_frags++;
	}

	skb_shinfo(skb)->frags[0].page_offset += hdr_len;
	skb_shinfo(skb)->frags[0].size -= 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,
					  struct vlan_group *vgrp,
					  u16 vlan_tag, 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 = page_address(frags->page) + frags->page_offset;
		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, 0, NULL);
		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, NULL, 0, priv)) {
		if (lro_mgr->features & LRO_F_NAPI)
			netif_receive_skb(skb);
		else
			netif_rx(skb);
	}
}
EXPORT_SYMBOL(lro_receive_skb);

void lro_vlan_hwaccel_receive_skb(struct net_lro_mgr *lro_mgr,
				  struct sk_buff *skb,
				  struct vlan_group *vgrp,
				  u16 vlan_tag,
				  void *priv)
{
	if (__lro_proc_skb(lro_mgr, skb, vgrp, vlan_tag, priv)) {
		if (lro_mgr->features & LRO_F_NAPI)
			vlan_hwaccel_receive_skb(skb, vgrp, vlan_tag);
		else
			vlan_hwaccel_rx(skb, vgrp, vlan_tag);
	}
}
EXPORT_SYMBOL(lro_vlan_hwaccel_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, NULL, 0,
				 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_vlan_hwaccel_receive_frags(struct net_lro_mgr *lro_mgr,
				    struct skb_frag_struct *frags,
				    int len, int true_size,
				    struct vlan_group *vgrp,
				    u16 vlan_tag, void *priv, __wsum sum)
{
	struct sk_buff *skb;

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

	if (lro_mgr->features & LRO_F_NAPI)
		vlan_hwaccel_receive_skb(skb, vgrp, vlan_tag);
	else
		vlan_hwaccel_rx(skb, vgrp, vlan_tag);
}
EXPORT_SYMBOL(lro_vlan_hwaccel_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 <themann@de.ibm.com>
	10	* Christoph Raisch <raisch@de.ibm.com>
	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 <themann@de.ibm.com>");
	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
	54	static int lro_tcp_ip_check(struct iphdr iph, struct tcphdr tcph,
	55	int len, struct net_lro_desc *lro_desc)
	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
67	if (tcph->cwr \|\| tcph->ece \|\| tcph->urg \|\| !tcph->ack
68	\|\| tcph->rst \|\| tcph->syn \|\| tcph->fin)
69	return -1;
70
71	if (INET_ECN_is_ce(ipv4_get_dsfield(iph)))
72	return -1;
73
74	if (tcph->doff != TCPH_LEN_WO_OPTIONS
75	&& tcph->doff != TCPH_LEN_W_TIMESTAMP)
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;
	123	tcp_hdr_csum = csum_partial((u8 *)tcph, TCP_HDR_LEN(tcph), 0);
	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);
	138	tcp_hdr_csum = csum_partial((u8 *)tcph, TCP_HDR_LEN(tcph), tcp_csum);
	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,
	149	struct iphdr iph, struct tcphdr tcph,
	150	u16 vlan_tag, struct vlan_group *vgrp)
	151	{
	152	int nr_frags;
9df7c98a	153	__be32 *ptr;
71c87e0c JBT	154	u32 tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
	155
	156	nr_frags = skb_shinfo(skb)->nr_frags;
	157	lro_desc->parent = skb;
	158	lro_desc->next_frag = &(skb_shinfo(skb)->frags[nr_frags]);
	159	lro_desc->iph = iph;
	160	lro_desc->tcph = tcph;
	161	lro_desc->tcp_next_seq = ntohl(tcph->seq) + tcp_data_len;
f53f4137	162	lro_desc->tcp_ack = tcph->ack_seq;
71c87e0c JBT	163	lro_desc->tcp_window = tcph->window;
	164
	165	lro_desc->pkt_aggr_cnt = 1;
	166	lro_desc->ip_tot_len = ntohs(iph->tot_len);
	167
	168	if (tcph->doff == 8) {
9df7c98a	169	ptr = (__be32 *)(tcph+1);
71c87e0c JBT	170	lro_desc->tcp_saw_tstamp = 1;
	171	lro_desc->tcp_rcv_tsval = *(ptr+1);
	172	lro_desc->tcp_rcv_tsecr = *(ptr+2);
	173	}
	174
	175	lro_desc->mss = tcp_data_len;
	176	lro_desc->vgrp = vgrp;
	177	lro_desc->vlan_tag = vlan_tag;
	178	lro_desc->active = 1;
	179
	180	lro_desc->data_csum = lro_tcp_data_csum(iph, tcph,
	181	tcp_data_len);
	182	}
	183
	184	static inline void lro_clear_desc(struct net_lro_desc *lro_desc)
	185	{
	186	memset(lro_desc, 0, sizeof(struct net_lro_desc));
	187	}
	188
	189	static void lro_add_common(struct net_lro_desc lro_desc, struct iphdr iph,
	190	struct tcphdr *tcph, int tcp_data_len)
	191	{
	192	struct sk_buff *parent = lro_desc->parent;
9df7c98a	193	__be32 *topt;
71c87e0c JBT	194
	195	lro_desc->pkt_aggr_cnt++;
	196	lro_desc->ip_tot_len += tcp_data_len;
	197	lro_desc->tcp_next_seq += tcp_data_len;
	198	lro_desc->tcp_window = tcph->window;
	199	lro_desc->tcp_ack = tcph->ack_seq;
	200
	201	/* don't update tcp_rcv_tsval, would not work with PAWS */
	202	if (lro_desc->tcp_saw_tstamp) {
9df7c98a	203	topt = (__be32 *) (tcph + 1);
71c87e0c JBT	204	lro_desc->tcp_rcv_tsecr = *(topt + 2);
	205	}
	206
	207	lro_desc->data_csum = csum_block_add(lro_desc->data_csum,
	208	lro_tcp_data_csum(iph, tcph,
	209	tcp_data_len),
	210	parent->len);
	211
	212	parent->len += tcp_data_len;
	213	parent->data_len += tcp_data_len;
	214	if (tcp_data_len > lro_desc->mss)
	215	lro_desc->mss = tcp_data_len;
	216	}
	217
	218	static void lro_add_packet(struct net_lro_desc lro_desc, struct sk_buff skb,
	219	struct iphdr iph, struct tcphdr tcph)
	220	{
	221	struct sk_buff *parent = lro_desc->parent;
	222	int tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
	223
	224	lro_add_common(lro_desc, iph, tcph, tcp_data_len);
	225
	226	skb_pull(skb, (skb->len - tcp_data_len));
	227	parent->truesize += skb->truesize;
	228
	229	if (lro_desc->last_skb)
	230	lro_desc->last_skb->next = skb;
	231	else
	232	skb_shinfo(parent)->frag_list = skb;
	233
	234	lro_desc->last_skb = skb;
	235	}
	236
	237	static void lro_add_frags(struct net_lro_desc *lro_desc,
	238	int len, int hlen, int truesize,
	239	struct skb_frag_struct *skb_frags,
	240	struct iphdr iph, struct tcphdr tcph)
	241	{
	242	struct sk_buff *skb = lro_desc->parent;
	243	int tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
	244
	245	lro_add_common(lro_desc, iph, tcph, tcp_data_len);
	246
	247	skb->truesize += truesize;
	248
	249	skb_frags[0].page_offset += hlen;
	250	skb_frags[0].size -= hlen;
	251
	252	while (tcp_data_len > 0) {
	253	(lro_desc->next_frag) = skb_frags;
	254	tcp_data_len -= skb_frags->size;
	255	lro_desc->next_frag++;
	256	skb_frags++;
	257	skb_shinfo(skb)->nr_frags++;
	258	}
	259	}
	260
	261	static int lro_check_tcp_conn(struct net_lro_desc *lro_desc,
	262	struct iphdr *iph,
	263	struct tcphdr *tcph)
	264	{
	265	if ((lro_desc->iph->saddr != iph->saddr)
	266	\|\| (lro_desc->iph->daddr != iph->daddr)
	267	\|\| (lro_desc->tcph->source != tcph->source)
268	\|\| (lro_desc->tcph->dest != tcph->dest))
269	return -1;
270	return 0;
271	}
272
273	static struct net_lro_desc lro_get_desc(struct net_lro_mgr lro_mgr,
274	struct net_lro_desc *lro_arr,
275	struct iphdr *iph,
276	struct tcphdr *tcph)
277	{
278	struct net_lro_desc *lro_desc = NULL;
279	struct net_lro_desc *tmp;
280	int max_desc = lro_mgr->max_desc;
281	int i;
282
283	for (i = 0; i < max_desc; i++) {
284	tmp = &lro_arr[i];
285	if (tmp->active)
286	if (!lro_check_tcp_conn(tmp, iph, tcph)) {
287	lro_desc = tmp;
288	goto out;
289	}
290	}
291
292	for (i = 0; i < max_desc; i++) {
293	if (!lro_arr[i].active) {
294	lro_desc = &lro_arr[i];
295	goto out;
296	}
297	}
298
299	LRO_INC_STATS(lro_mgr, no_desc);
300	out:
301	return lro_desc;
302	}
303
304	static void lro_flush(struct net_lro_mgr *lro_mgr,
305	struct net_lro_desc *lro_desc)
306	{
307	if (lro_desc->pkt_aggr_cnt > 1)
308	lro_update_tcp_ip_header(lro_desc);
309
310	skb_shinfo(lro_desc->parent)->gso_size = lro_desc->mss;
311
312	if (lro_desc->vgrp) {
877364e6	313	if (lro_mgr->features & LRO_F_NAPI)
71c87e0c JBT	314	vlan_hwaccel_receive_skb(lro_desc->parent,
	315	lro_desc->vgrp,
	316	lro_desc->vlan_tag);
	317	else
	318	vlan_hwaccel_rx(lro_desc->parent,
	319	lro_desc->vgrp,
	320	lro_desc->vlan_tag);
	321
	322	} else {
877364e6	323	if (lro_mgr->features & LRO_F_NAPI)
71c87e0c JBT	324	netif_receive_skb(lro_desc->parent);
	325	else
	326	netif_rx(lro_desc->parent);
	327	}
	328
	329	LRO_INC_STATS(lro_mgr, flushed);
	330	lro_clear_desc(lro_desc);
	331	}
	332
	333	static int __lro_proc_skb(struct net_lro_mgr lro_mgr, struct sk_buff skb,
	334	struct vlan_group vgrp, u16 vlan_tag, void priv)
	335	{
	336	struct net_lro_desc *lro_desc;
	337	struct iphdr *iph;
	338	struct tcphdr *tcph;
	339	u64 flags;
	340	int vlan_hdr_len = 0;
	341
	342	if (!lro_mgr->get_skb_header
	343	\|\| lro_mgr->get_skb_header(skb, (void )&iph, (void )&tcph,
	344	&flags, priv))
	345	goto out;
	346
	347	if (!(flags & LRO_IPV4) \|\| !(flags & LRO_TCP))
	348	goto out;
	349
	350	lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
	351	if (!lro_desc)
	352	goto out;
	353
	354	if ((skb->protocol == htons(ETH_P_8021Q))
877364e6	355	&& !(lro_mgr->features & LRO_F_EXTRACT_VLAN_ID))
71c87e0c JBT	356	vlan_hdr_len = VLAN_HLEN;
	357
	358	if (!lro_desc->active) { /* start new lro session */
	359	if (lro_tcp_ip_check(iph, tcph, skb->len - vlan_hdr_len, NULL))
	360	goto out;
	361
	362	skb->ip_summed = lro_mgr->ip_summed_aggr;
	363	lro_init_desc(lro_desc, skb, iph, tcph, vlan_tag, vgrp);
	364	LRO_INC_STATS(lro_mgr, aggregated);
	365	return 0;
	366	}
	367
	368	if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
	369	goto out2;
	370
	371	if (lro_tcp_ip_check(iph, tcph, skb->len, lro_desc))
	372	goto out2;
	373
	374	lro_add_packet(lro_desc, skb, iph, tcph);
	375	LRO_INC_STATS(lro_mgr, aggregated);
	376
	377	if ((lro_desc->pkt_aggr_cnt >= lro_mgr->max_aggr) \|\|
	378	lro_desc->parent->len > (0xFFFF - lro_mgr->dev->mtu))
	379	lro_flush(lro_mgr, lro_desc);
	380
	381	return 0;
	382
	383	out2: /* send aggregated SKBs to stack */
	384	lro_flush(lro_mgr, lro_desc);
	385
	386	out: /* Original SKB has to be posted to stack */
	387	skb->ip_summed = lro_mgr->ip_summed;
	388	return 1;
	389	}
	390
	391
	392	static struct sk_buff lro_gen_skb(struct net_lro_mgr lro_mgr,
	393	struct skb_frag_struct *frags,
	394	int len, int true_size,
	395	void *mac_hdr,
	396	int hlen, __wsum sum,
	397	u32 ip_summed)
	398	{
	399	struct sk_buff *skb;
	400	struct skb_frag_struct *skb_frags;
	401	int data_len = len;
	402	int hdr_len = min(len, hlen);
	403
621544eb	404	skb = netdev_alloc_skb(lro_mgr->dev, hlen + lro_mgr->frag_align_pad);
71c87e0c JBT	405	if (!skb)
	406	return NULL;
	407
621544eb	408	skb_reserve(skb, lro_mgr->frag_align_pad);
71c87e0c JBT	409	skb->len = len;
	410	skb->data_len = len - hdr_len;
	411	skb->truesize += true_size;
	412	skb->tail += hdr_len;
	413
	414	memcpy(skb->data, mac_hdr, hdr_len);
	415
	416	skb_frags = skb_shinfo(skb)->frags;
	417	while (data_len > 0) {
	418	skb_frags = frags;
	419	data_len -= frags->size;
	420	skb_frags++;
	421	frags++;
	422	skb_shinfo(skb)->nr_frags++;
	423	}
	424
	425	skb_shinfo(skb)->frags[0].page_offset += hdr_len;
	426	skb_shinfo(skb)->frags[0].size -= hdr_len;
	427
	428	skb->ip_summed = ip_summed;
	429	skb->csum = sum;
	430	skb->protocol = eth_type_trans(skb, lro_mgr->dev);
	431	return skb;
	432	}
	433
	434	static struct sk_buff __lro_proc_segment(struct net_lro_mgr lro_mgr,
	435	struct skb_frag_struct *frags,
	436	int len, int true_size,
	437	struct vlan_group *vgrp,
	438	u16 vlan_tag, void *priv, __wsum sum)
	439	{
	440	struct net_lro_desc *lro_desc;
	441	struct iphdr *iph;
	442	struct tcphdr *tcph;
	443	struct sk_buff *skb;
	444	u64 flags;
	445	void *mac_hdr;
	446	int mac_hdr_len;
	447	int hdr_len = LRO_MAX_PG_HLEN;
	448	int vlan_hdr_len = 0;
	449
	450	if (!lro_mgr->get_frag_header
	451	\|\| lro_mgr->get_frag_header(frags, (void )&mac_hdr, (void )&iph,
	452	(void *)&tcph, &flags, priv)) {
	453	mac_hdr = page_address(frags->page) + frags->page_offset;
	454	goto out1;
	455	}
	456
	457	if (!(flags & LRO_IPV4) \|\| !(flags & LRO_TCP))
	458	goto out1;
	459
	460	hdr_len = (int)((void *)(tcph) + TCP_HDR_LEN(tcph) - mac_hdr);
	461	mac_hdr_len = (int)((void *)(iph) - mac_hdr);
	462
	463	lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
	464	if (!lro_desc)
	465	goto out1;
	466
	467	if (!lro_desc->active) { /* start new lro session */
	468	if (lro_tcp_ip_check(iph, tcph, len - mac_hdr_len, NULL))
	469	goto out1;
	470
	471	skb = lro_gen_skb(lro_mgr, frags, len, true_size, mac_hdr,
	472	hdr_len, 0, lro_mgr->ip_summed_aggr);
473	if (!skb)
474	goto out;
475
476	if ((skb->protocol == htons(ETH_P_8021Q))
877364e6	477	&& !(lro_mgr->features & LRO_F_EXTRACT_VLAN_ID))
71c87e0c JBT	478	vlan_hdr_len = VLAN_HLEN;
	479
	480	iph = (void *)(skb->data + vlan_hdr_len);
	481	tcph = (void )((u8 )skb->data + vlan_hdr_len
	482	+ IP_HDR_LEN(iph));
	483
	484	lro_init_desc(lro_desc, skb, iph, tcph, 0, NULL);
	485	LRO_INC_STATS(lro_mgr, aggregated);
cfcabdcc	486	return NULL;
71c87e0c JBT	487	}
	488
	489	if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
	490	goto out2;
	491
	492	if (lro_tcp_ip_check(iph, tcph, len - mac_hdr_len, lro_desc))
	493	goto out2;
	494
	495	lro_add_frags(lro_desc, len, hdr_len, true_size, frags, iph, tcph);
	496	LRO_INC_STATS(lro_mgr, aggregated);
	497
	498	if ((skb_shinfo(lro_desc->parent)->nr_frags >= lro_mgr->max_aggr) \|\|
	499	lro_desc->parent->len > (0xFFFF - lro_mgr->dev->mtu))
	500	lro_flush(lro_mgr, lro_desc);
	501
	502	return NULL;
	503
	504	out2: /* send aggregated packets to the stack */
	505	lro_flush(lro_mgr, lro_desc);
	506
	507	out1: /* Original packet has to be posted to the stack */
	508	skb = lro_gen_skb(lro_mgr, frags, len, true_size, mac_hdr,
	509	hdr_len, sum, lro_mgr->ip_summed);
	510	out:
	511	return skb;
	512	}
	513
	514	void lro_receive_skb(struct net_lro_mgr *lro_mgr,
	515	struct sk_buff *skb,
	516	void *priv)
	517	{
	518	if (__lro_proc_skb(lro_mgr, skb, NULL, 0, priv)) {
877364e6	519	if (lro_mgr->features & LRO_F_NAPI)
71c87e0c JBT	520	netif_receive_skb(skb);
	521	else
	522	netif_rx(skb);
	523	}
	524	}
	525	EXPORT_SYMBOL(lro_receive_skb);
	526
	527	void lro_vlan_hwaccel_receive_skb(struct net_lro_mgr *lro_mgr,
	528	struct sk_buff *skb,
	529	struct vlan_group *vgrp,
	530	u16 vlan_tag,
	531	void *priv)
	532	{
	533	if (__lro_proc_skb(lro_mgr, skb, vgrp, vlan_tag, priv)) {
877364e6	534	if (lro_mgr->features & LRO_F_NAPI)
71c87e0c JBT	535	vlan_hwaccel_receive_skb(skb, vgrp, vlan_tag);
	536	else
	537	vlan_hwaccel_rx(skb, vgrp, vlan_tag);
	538	}
	539	}
	540	EXPORT_SYMBOL(lro_vlan_hwaccel_receive_skb);
	541
	542	void lro_receive_frags(struct net_lro_mgr *lro_mgr,
	543	struct skb_frag_struct *frags,
	544	int len, int true_size, void *priv, __wsum sum)
	545	{
	546	struct sk_buff *skb;
	547
	548	skb = __lro_proc_segment(lro_mgr, frags, len, true_size, NULL, 0,
	549	priv, sum);
	550	if (!skb)
	551	return;
	552
877364e6	553	if (lro_mgr->features & LRO_F_NAPI)
71c87e0c JBT	554	netif_receive_skb(skb);
	555	else
	556	netif_rx(skb);
	557	}
	558	EXPORT_SYMBOL(lro_receive_frags);
	559
	560	void lro_vlan_hwaccel_receive_frags(struct net_lro_mgr *lro_mgr,
	561	struct skb_frag_struct *frags,
	562	int len, int true_size,
	563	struct vlan_group *vgrp,
	564	u16 vlan_tag, void *priv, __wsum sum)
	565	{
	566	struct sk_buff *skb;
	567
	568	skb = __lro_proc_segment(lro_mgr, frags, len, true_size, vgrp,
	569	vlan_tag, priv, sum);
	570	if (!skb)
	571	return;
	572
877364e6	573	if (lro_mgr->features & LRO_F_NAPI)
71c87e0c JBT	574	vlan_hwaccel_receive_skb(skb, vgrp, vlan_tag);
	575	else
	576	vlan_hwaccel_rx(skb, vgrp, vlan_tag);
	577	}
	578	EXPORT_SYMBOL(lro_vlan_hwaccel_receive_frags);
	579
	580	void lro_flush_all(struct net_lro_mgr *lro_mgr)
	581	{
	582	int i;
	583	struct net_lro_desc *lro_desc = lro_mgr->lro_arr;
	584
	585	for (i = 0; i < lro_mgr->max_desc; i++) {
	586	if (lro_desc[i].active)
	587	lro_flush(lro_mgr, &lro_desc[i]);
	588	}
	589	}
	590	EXPORT_SYMBOL(lro_flush_all);
	591
	592	void lro_flush_pkt(struct net_lro_mgr *lro_mgr,
	593	struct iphdr iph, struct tcphdr tcph)
	594	{
	595	struct net_lro_desc *lro_desc;
	596
	597	lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
	598	if (lro_desc->active)
	599	lro_flush(lro_mgr, lro_desc);
	600	}
	601	EXPORT_SYMBOL(lro_flush_pkt);