Large Receive Offload (tcp)
Signed-off-by: Jan-Bernd Themann <[email protected]>
---
include/linux/inet_lro.h | 107 ++++++++++++++++
net/ipv4/inet_lro.c | 311 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 418 insertions(+), 0 deletions(-)
create mode 100644 include/linux/inet_lro.h
create mode 100644 net/ipv4/inet_lro.c
diff --git a/include/linux/inet_lro.h b/include/linux/inet_lro.h
new file mode 100644
index 0000000..6df444a
--- /dev/null
+++ b/include/linux/inet_lro.h
@@ -0,0 +1,107 @@
+/*
+ * linux/include/linux/inet_lro.h
+ *
+ * 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.
+ */
+
+#ifndef __INET_LRO_H_
+#define __INET_LRO_H_
+
+#include <net/ip.h>
+#include <net/tcp.h>
+
+/*
+ * LRO descriptor for a tcp session
+ */
+struct net_lro_desc {
+ struct sk_buff *parent;
+ struct sk_buff *last_skb;
+ struct iphdr *iph;
+ struct tcphdr *tcph;
+ struct vlan_group *vgrp;
+ u32 tcp_rcv_tsecr;
+ u32 tcp_rcv_tsval;
+ u32 tcp_ack;
+ u32 tcp_next_seq;
+ u32 skb_tot_frags_len;
+ u16 ip_tot_len;
+ u16 tcp_saw_tstamp; /* timestamps enabled */
+ u16 tcp_window;
+ u16 vlan_tag;
+ int skb_sg_cnt; /* counts aggregated skbs */
+ int vlan_packet;
+ int active;
+};
+
+/*
+ * Large Receive Offload (LRO) Manager
+ *
+ * Fields must be set by driver
+ */
+
+struct net_lro_mgr {
+ int max_desc; /* Max number of LRO descriptors */
+ int max_aggr; /* Max number of LRO packets to be aggregated */
+
+ struct net_lro_desc *lro_arr; /* Array of LRO descriptors */
+
+ /*
+ * Optimized driver functions
+ *
+ * get_tcp_ip_hdr: returns tcp and ip header for packet in SKB
+ */
+ int (*get_ip_tcp_hdr)(struct sk_buff *skb, struct iphdr **iphdr,
+ struct tcphdr **tcph, void *priv);
+};
+
+/*
+ * Processes a SKB
+ *
+ * @lro_mgr: LRO manager to use
+ * @skb: SKB to aggregate
+ * @priv: Private data that may be used by driver functions
+ * (for example get_tcp_ip_hdr)
+ */
+
+void lro_receive_skb(struct net_lro_mgr *lro_mgr,
+ struct sk_buff *skb,
+ void *priv);
+
+/*
+ * Processes a SKB with VLAN HW acceleration support
+ */
+
+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);
+
+/*
+ * Forward all aggregated SKBs held by lro_mgr to network stack
+ */
+
+void lro_flush_all(struct net_lro_mgr *lro_mgr);
+
+#endif
diff --git a/net/ipv4/inet_lro.c b/net/ipv4/inet_lro.c
new file mode 100644
index 0000000..2b9d871
--- /dev/null
+++ b/net/ipv4/inet_lro.c
@@ -0,0 +1,311 @@
+/*
+ * 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_PAYLOAD_LENGTH(iph, tcph) \
+(ntohs(iph->tot_len) - (iph->ihl << 2) - (tcph->doff << 2))
+
+#define IPH_LEN_WO_OPTIONS 5
+#define TCPH_LEN_WO_OPTIONS 5
+#define TCPH_LEN_W_TIMESTAMP 8
+
+/*
+ * Basic tcp checks whether packet is suitable for LRO
+ */
+
+static int lro_tcp_ip_check(struct sk_buff *skb, struct iphdr *iph,
+ struct tcphdr *tcph, struct net_lro_desc *lro_desc)
+{
+ /* check ip header: packet length */
+ if (ntohs(iph->tot_len) > skb->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->psh
+ || 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 && (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;
+
+ 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);
+}
+
+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)
+{
+ u32 *ptr;
+ u32 tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
+
+ lro_desc->parent = skb;
+ 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->skb_sg_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->vgrp = vgrp;
+ lro_desc->vlan_tag = vlan_tag;
+ lro_desc->active = 1;
+}
+
+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_packet(struct net_lro_desc *lro_desc, struct sk_buff *skb,
+ struct iphdr *iph, struct tcphdr *tcph)
+{
+ struct sk_buff *parent = lro_desc->parent;
+ u32 *topt;
+ u32 tcp_data_len = TCP_PAYLOAD_LENGTH(iph, tcph);
+
+ lro_desc->skb_sg_cnt++;
+
+ lro_desc->ip_tot_len += tcp_data_len;
+ lro_desc->tcp_next_seq += tcp_data_len;
+ lro_desc->tcp_window = lro_desc->tcph->window;
+ lro_desc->tcp_ack = lro_desc->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);
+ }
+
+ parent->len += tcp_data_len;
+ parent->data_len += 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;
+
+ return;
+}
+
+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 *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 = 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;
+ }
+ }
+
+out:
+ return lro_desc;
+}
+
+static void lro_flush(struct net_lro_desc *lro_desc)
+{
+ lro_update_tcp_ip_header(lro_desc);
+
+ if (lro_desc->vgrp)
+ vlan_hwaccel_receive_skb(lro_desc->parent, lro_desc->vgrp,
+ lro_desc->vlan_tag);
+ else
+ netif_receive_skb(lro_desc->parent);
+
+ lro_clear_desc(lro_desc);
+}
+
+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_desc[i]);
+ }
+}
+EXPORT_SYMBOL(lro_flush_all);
+
+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;
+
+ if (!lro_mgr->get_ip_tcp_hdr
+ || lro_mgr->get_ip_tcp_hdr(skb, &iph, &tcph, priv))
+ goto out;
+
+ lro_desc = lro_get_desc(lro_mgr, lro_mgr->lro_arr, iph, tcph);
+ if (!lro_desc)
+ goto out;
+
+ if (!lro_desc->active) { /* start new lro session */
+ if (lro_tcp_ip_check(skb, iph, tcph, NULL))
+ goto out;
+
+ lro_init_desc(lro_desc, skb, iph, tcph, vlan_tag, vgrp);
+ return 0;
+ }
+
+ if (lro_desc->tcp_next_seq != ntohl(tcph->seq))
+ goto out2;
+
+ if (lro_tcp_ip_check(skb, iph, tcph, lro_desc))
+ goto out2;
+
+ lro_add_packet(lro_desc, skb, iph, tcph);
+
+ if (lro_desc->skb_sg_cnt >= lro_mgr->max_aggr)
+ lro_flush(lro_desc);
+
+ return 0;
+
+out2: /* send aggregated SKBs to stack */
+ lro_flush(lro_desc);
+
+out: /* Original SKB has to be posted to stack */
+ return 1;
+}
+
+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))
+ netif_receive_skb(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))
+ vlan_hwaccel_receive_skb(skb, vgrp, vlan_tag);
+}
+EXPORT_SYMBOL(lro_vlan_hwaccel_receive_skb);
--
1.5.2
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