/* * 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(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, 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);