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DEFINITIONS
This source file includes following definitions.
- lro_tcp_ip_check
- lro_update_tcp_ip_header
- lro_tcp_data_csum
- lro_init_desc
- lro_clear_desc
- lro_add_common
- lro_add_packet
- lro_add_frags
- lro_check_tcp_conn
- lro_get_desc
- lro_flush
- __lro_proc_skb
- lro_gen_skb
- __lro_proc_segment
- lro_receive_skb
- lro_vlan_hwaccel_receive_skb
- lro_receive_frags
- lro_vlan_hwaccel_receive_frags
- lro_flush_all
- lro_flush_pkt
/*
* 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:
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);