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v4 GRE: Add TCP segmentation offload for GRE

Browse Source 
Following patch adds GRE protocol offload handler so that
skb_gso_segment() can segment GRE packets.
SKB GSO CB is added to keep track of total header length so that
skb_segment can push entire header. e.g. in case of GRE, skb_segment
need to push inner and outer headers to every segment.
New NETIF_F_GRE_GSO feature is added for devices which support HW
GRE TSO offload. Currently none of devices support it therefore GRE GSO
always fall backs to software GSO.

[ Compute pkt_len before ip_local_out() invocation. -DaveM ]

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tirimbino
Pravin B Shelar 12 years ago committed by David S. Miller
parent 05e8ef4ab2
commit 68c3316311
12 changed files with 226 additions and 11 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 3
      include/linux/netdev_features.h
  2. 17
      include/linux/skbuff.h
  3. 1
      net/core/dev.c
  4. 1
      net/core/ethtool.c
  5. 6
      net/core/skbuff.c
  6. 1
      net/ipv4/af_inet.c
  7. 118
      net/ipv4/gre.c
  8. 82
      net/ipv4/ip_gre.c
  9. 1
      net/ipv4/tcp.c
  10. 3
      net/ipv4/udp.c
  11. 1
      net/ipv6/ip6_offload.c
  12. 3
      net/ipv6/udp_offload.c

3
include/linux/netdev_features.h
Unescape View File

@ -41,7 +41,7 @@ enum {
NETIF_F_TSO_ECN_BIT, /* ... TCP ECN support */
NETIF_F_TSO6_BIT, /* ... TCPv6 segmentation */
NETIF_F_FSO_BIT, /* ... FCoE segmentation */
NETIF_F_GSO_RESERVED1, /* ... free (fill GSO_MASK to 8 bits) */
NETIF_F_GSO_GRE_BIT, /* ... GRE with TSO */
/**/NETIF_F_GSO_LAST, /* [can't be last bit, see GSO_MASK] */
NETIF_F_GSO_RESERVED2 /* ... free (fill GSO_MASK to 8 bits) */
= NETIF_F_GSO_LAST,
@ -102,6 +102,7 @@ enum {
#define NETIF_F_VLAN_CHALLENGED __NETIF_F(VLAN_CHALLENGED)
#define NETIF_F_RXFCS __NETIF_F(RXFCS)
#define NETIF_F_RXALL __NETIF_F(RXALL)
#define NETIF_F_GRE_GSO __NETIF_F(GSO_GRE)
/* Features valid for ethtool to change */
/* = all defined minus driver/device-class-related */

17
include/linux/skbuff.h
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@ -314,6 +314,8 @@ enum {
SKB_GSO_TCPV6 = 1 << 4,
SKB_GSO_FCOE = 1 << 5,
SKB_GSO_GRE = 1 << 6,
};
#if BITS_PER_LONG > 32
@ -2732,6 +2734,21 @@ static inline struct sec_path *skb_sec_path(struct sk_buff *skb)
}
#endif
/* Keeps track of mac header offset relative to skb->head.
* It is useful for TSO of Tunneling protocol. e.g. GRE.
* For non-tunnel skb it points to skb_mac_header() and for
* tunnel skb it points to outer mac header. */
struct skb_gso_cb {
int mac_offset;
};
#define SKB_GSO_CB(skb) ((struct skb_gso_cb *)(skb)->cb)
static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
{
return (skb_mac_header(inner_skb) - inner_skb->head) -
SKB_GSO_CB(inner_skb)->mac_offset;
}
static inline bool skb_is_gso(const struct sk_buff *skb)
{
return skb_shinfo(skb)->gso_size;

1
net/core/dev.c
Unescape View File

@ -2413,6 +2413,7 @@ struct sk_buff *__skb_gso_segment(struct sk_buff *skb,
return ERR_PTR(err);
}
SKB_GSO_CB(skb)->mac_offset = skb_headroom(skb);
skb_reset_mac_header(skb);
skb_reset_mac_len(skb);

1
net/core/ethtool.c
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@ -77,6 +77,7 @@ static const char netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN]
[NETIF_F_TSO_ECN_BIT] = "tx-tcp-ecn-segmentation",
[NETIF_F_TSO6_BIT] = "tx-tcp6-segmentation",
[NETIF_F_FSO_BIT] = "tx-fcoe-segmentation",
[NETIF_F_GSO_GRE_BIT] = "tx-gre-segmentation",
[NETIF_F_FCOE_CRC_BIT] = "tx-checksum-fcoe-crc",
[NETIF_F_SCTP_CSUM_BIT] = "tx-checksum-sctp",

6
net/core/skbuff.c
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@ -2738,6 +2738,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
unsigned int mss = skb_shinfo(skb)->gso_size;
unsigned int doffset = skb->data - skb_mac_header(skb);
unsigned int offset = doffset;
unsigned int tnl_hlen = skb_tnl_header_len(skb);
unsigned int headroom;
unsigned int len;
int sg = !!(features & NETIF_F_SG);
@ -2814,7 +2815,10 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
skb_set_network_header(nskb, skb->mac_len);
nskb->transport_header = (nskb->network_header +
skb_network_header_len(skb));
skb_copy_from_linear_data(skb, nskb->data, doffset);
skb_copy_from_linear_data_offset(skb, -tnl_hlen,
nskb->data - tnl_hlen,
doffset + tnl_hlen);
if (fskb != skb_shinfo(skb)->frag_list)
continue;

1
net/ipv4/af_inet.c
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@ -1287,6 +1287,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
SKB_GSO_UDP |
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
SKB_GSO_GRE |
0)))
goto out;

118
net/ipv4/gre.c
Unescape View File

@ -19,6 +19,7 @@
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/netdevice.h>
#include <linux/if_tunnel.h>
#include <linux/spinlock.h>
#include <net/protocol.h>
#include <net/gre.h>
@ -26,6 +27,11 @@
static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
static DEFINE_SPINLOCK(gre_proto_lock);
struct gre_base_hdr {
__be16 flags;
__be16 protocol;
};
#define GRE_HEADER_SECTION 4
int gre_add_protocol(const struct gre_protocol *proto, u8 version)
{
@ -112,12 +118,117 @@ static void gre_err(struct sk_buff *skb, u32 info)
rcu_read_unlock();
}
static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
netdev_features_t enc_features;
int ghl = GRE_HEADER_SECTION;
struct gre_base_hdr *greh;
int mac_len = skb->mac_len;
int tnl_hlen;
bool csum;
if (unlikely(skb_shinfo(skb)->gso_type &
~(SKB_GSO_TCPV4 |
SKB_GSO_TCPV6 |
SKB_GSO_UDP |
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
SKB_GSO_GRE)))
goto out;
if (unlikely(!pskb_may_pull(skb, sizeof(*greh))))
goto out;
greh = (struct gre_base_hdr *)skb_transport_header(skb);
if (greh->flags & GRE_KEY)
ghl += GRE_HEADER_SECTION;
if (greh->flags & GRE_SEQ)
ghl += GRE_HEADER_SECTION;
if (greh->flags & GRE_CSUM) {
ghl += GRE_HEADER_SECTION;
csum = true;
} else
csum = false;
/* setup inner skb. */
if (greh->protocol == htons(ETH_P_TEB)) {
struct ethhdr *eth = eth_hdr(skb);
skb->protocol = eth->h_proto;
} else {
skb->protocol = greh->protocol;
}
skb->encapsulation = 0;
if (unlikely(!pskb_may_pull(skb, ghl)))
goto out;
__skb_pull(skb, ghl);
skb_reset_mac_header(skb);
skb_set_network_header(skb, skb_inner_network_offset(skb));
skb->mac_len = skb_inner_network_offset(skb);
/* segment inner packet. */
enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
segs = skb_mac_gso_segment(skb, enc_features);
if (!segs || IS_ERR(segs))
goto out;
skb = segs;
tnl_hlen = skb_tnl_header_len(skb);
do {
__skb_push(skb, ghl);
if (csum) {
__be32 *pcsum;
if (skb_has_shared_frag(skb)) {
int err;
err = __skb_linearize(skb);
if (err) {
kfree_skb(segs);
segs = ERR_PTR(err);
goto out;
}
}
greh = (struct gre_base_hdr *)(skb->data);
pcsum = (__be32 *)(greh + 1);
*pcsum = 0;
*(__sum16 *)pcsum = csum_fold(skb_checksum(skb, 0, skb->len, 0));
}
__skb_push(skb, tnl_hlen - ghl);
skb_reset_mac_header(skb);
skb_set_network_header(skb, mac_len);
skb->mac_len = mac_len;
} while ((skb = skb->next));
out:
return segs;
}
static int gre_gso_send_check(struct sk_buff *skb)
{
if (!skb->encapsulation)
return -EINVAL;
return 0;
}
static const struct net_protocol net_gre_protocol = {
.handler = gre_rcv,
.err_handler = gre_err,
.netns_ok = 1,
};
static const struct net_offload gre_offload = {
.callbacks = {
.gso_send_check = gre_gso_send_check,
.gso_segment = gre_gso_segment,
},
};
static int __init gre_init(void)
{
pr_info("GRE over IPv4 demultiplexor driver\n");
@ -127,11 +238,18 @@ static int __init gre_init(void)
return -EAGAIN;
}
if (inet_add_offload(&gre_offload, IPPROTO_GRE)) {
pr_err("can't add protocol offload\n");
inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
return -EAGAIN;
}
return 0;
}
static void __exit gre_exit(void)
{
inet_del_offload(&gre_offload, IPPROTO_GRE);
inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
}

82
net/ipv4/ip_gre.c
Unescape View File

@ -735,8 +735,33 @@ drop:
return 0;
}
static struct sk_buff *handle_offloads(struct sk_buff *skb)
{
int err;
if (skb_is_gso(skb)) {
err = skb_unclone(skb, GFP_ATOMIC);
if (unlikely(err))
goto error;
skb_shinfo(skb)->gso_type |= SKB_GSO_GRE;
return skb;
} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
err = skb_checksum_help(skb);
if (unlikely(err))
goto error;
}
skb->ip_summed = CHECKSUM_NONE;
return skb;
error:
kfree_skb(skb);
return ERR_PTR(err);
}
static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct pcpu_tstats *tstats = this_cpu_ptr(dev->tstats);
struct ip_tunnel *tunnel = netdev_priv(dev);
const struct iphdr *old_iph;
const struct iphdr *tiph;
@ -751,10 +776,19 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
__be32 dst;
int mtu;
u8 ttl;
int err;
int pkt_len;
if (skb->ip_summed == CHECKSUM_PARTIAL &&
skb_checksum_help(skb))
goto tx_error;
skb = handle_offloads(skb);
if (IS_ERR(skb)) {
dev->stats.tx_dropped++;
return NETDEV_TX_OK;
}
if (!skb->encapsulation) {
skb_reset_inner_headers(skb);
skb->encapsulation = 1;
}
old_iph = ip_hdr(skb);
@ -855,7 +889,8 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
if (skb->protocol == htons(ETH_P_IP)) {
df |= (old_iph->frag_off&htons(IP_DF));
if ((old_iph->frag_off&htons(IP_DF)) &&
if (!skb_is_gso(skb) &&
(old_iph->frag_off&htons(IP_DF)) &&
mtu < ntohs(old_iph->tot_len)) {
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
ip_rt_put(rt);
@ -875,7 +910,9 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
}
}
if (mtu >= IPV6_MIN_MTU && mtu < skb->len - tunnel->hlen + gre_hlen) {
if (!skb_is_gso(skb) &&
mtu >= IPV6_MIN_MTU &&
mtu < skb->len - tunnel->hlen + gre_hlen) {
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
ip_rt_put(rt);
goto tx_error;
@ -936,6 +973,7 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
iph->daddr = fl4.daddr;
iph->saddr = fl4.saddr;
iph->ttl = ttl;
iph->id = 0;
if (ttl == 0) {
if (skb->protocol == htons(ETH_P_IP))
@ -964,9 +1002,19 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
*ptr = tunnel->parms.o_key;
ptr--;
}
if (tunnel->parms.o_flags&GRE_CSUM) {
/* Skip GRE checksum if skb is getting offloaded. */
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_GRE) &&
(tunnel->parms.o_flags&GRE_CSUM)) {
int offset = skb_transport_offset(skb);
if (skb_has_shared_frag(skb)) {
err = __skb_linearize(skb);
if (err) {
ip_rt_put(rt);
goto tx_error;
}
}
*ptr = 0;
*(__sum16 *)ptr = csum_fold(skb_checksum(skb, offset,
skb->len - offset,
@ -974,7 +1022,19 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
}
}
iptunnel_xmit(skb, dev);
nf_reset(skb);
pkt_len = skb->len - skb_transport_offset(skb);
err = ip_local_out(skb);
if (likely(net_xmit_eval(err) == 0)) {
u64_stats_update_begin(&tstats->syncp);
tstats->tx_bytes += pkt_len;
tstats->tx_packets++;
u64_stats_update_end(&tstats->syncp);
} else {
dev->stats.tx_errors++;
dev->stats.tx_aborted_errors++;
}
return NETDEV_TX_OK;
#if IS_ENABLED(CONFIG_IPV6)
@ -1044,6 +1104,11 @@ static int ipgre_tunnel_bind_dev(struct net_device *dev)
mtu = 68;
tunnel->hlen = addend;
/* TCP offload with GRE SEQ is not supported. */
if (!(tunnel->parms.o_flags & GRE_SEQ)) {
dev->features |= NETIF_F_GSO_SOFTWARE;
dev->hw_features |= NETIF_F_GSO_SOFTWARE;
}
return mtu;
}
@ -1593,6 +1658,9 @@ static void ipgre_tap_setup(struct net_device *dev)
dev->iflink = 0;
dev->features |= NETIF_F_NETNS_LOCAL;
dev->features |= GRE_FEATURES;
dev->hw_features |= GRE_FEATURES;
}
static int ipgre_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[],

1
net/ipv4/tcp.c
Unescape View File

@ -3043,6 +3043,7 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb,
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
SKB_GSO_TCPV6 |
SKB_GSO_GRE |
0) ||
!(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
goto out;

3
net/ipv4/udp.c
Unescape View File

@ -2305,7 +2305,8 @@ struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
/* Packet is from an untrusted source, reset gso_segs. */
int type = skb_shinfo(skb)->gso_type;
if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
SKB_GSO_GRE) ||
!(type & (SKB_GSO_UDP))))
goto out;

1
net/ipv6/ip6_offload.c
Unescape View File

@ -99,6 +99,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
~(SKB_GSO_UDP |
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
SKB_GSO_GRE |
SKB_GSO_TCPV6 |
0)))
goto out;

3
net/ipv6/udp_offload.c
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@ -56,7 +56,8 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
/* Packet is from an untrusted source, reset gso_segs. */
int type = skb_shinfo(skb)->gso_type;
if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
SKB_GSO_GRE) ||
!(type & (SKB_GSO_UDP))))
goto out;

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