From 71c87e0cedca843162206c698cfa02e5fea9e2e3 Mon Sep 17 00:00:00 2001 From: Jan-Bernd Themann Date: Wed, 8 Aug 2007 22:38:05 -0700 Subject: [NET]: Generic Large Receive Offload for TCP traffic This patch provides generic Large Receive Offload (LRO) functionality for IPv4/TCP traffic. LRO combines received tcp packets to a single larger tcp packet and passes them then to the network stack in order to increase performance (throughput). The interface supports two modes: Drivers can either pass SKBs or fragment lists to the LRO engine. Signed-off-by: Jan-Bernd Themann Signed-off-by: David S. Miller --- net/ipv4/inet_lro.c | 600 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 600 insertions(+) create mode 100644 net/ipv4/inet_lro.c (limited to 'net/ipv4/inet_lro.c') diff --git a/net/ipv4/inet_lro.c b/net/ipv4/inet_lro.c new file mode 100644 index 00000000000..20bc593bb96 --- /dev/null +++ b/net/ipv4/inet_lro.c @@ -0,0 +1,600 @@ +/* + * linux/net/ipv4/inet_lro.c + * + * Large Receive Offload (ipv4 / tcp) + * + * (C) Copyright IBM Corp. 2007 + * + * Authors: + * Jan-Bernd Themann + * Christoph Raisch + * + * + * 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 +#include +#include + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jan-Bernd Themann "); +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) { + u32 *topt = (u32 *)(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; + u32 *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 = (u32 *)(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; + u32 *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 = ntohl(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 = (u32 *)(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; + u32 *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 = (u32 *) (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 (test_bit(LRO_F_NAPI, &lro_mgr->features)) + 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 (test_bit(LRO_F_NAPI, &lro_mgr->features)) + 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)) + && !test_bit(LRO_F_EXTRACT_VLAN_ID, &lro_mgr->features)) + 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); + if (!skb) + return NULL; + + 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)) + && !test_bit(LRO_F_EXTRACT_VLAN_ID, &lro_mgr->features)) + 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 0; + } + + 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 (test_bit(LRO_F_NAPI, &lro_mgr->features)) + 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 (test_bit(LRO_F_NAPI, &lro_mgr->features)) + 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 (test_bit(LRO_F_NAPI, &lro_mgr->features)) + 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 (test_bit(LRO_F_NAPI, &lro_mgr->features)) + 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); -- cgit v1.2.3