From 576a30eb6453439b3c37ba24455ac7090c247b5a Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 27 Jun 2006 13:22:38 -0700 Subject: [NET]: Added GSO header verification When GSO packets come from an untrusted source (e.g., a Xen guest domain), we need to verify the header integrity before passing it to the hardware. Since the first step in GSO is to verify the header, we can reuse that code by adding a new bit to gso_type: SKB_GSO_DODGY. Packets with this bit set can only be fed directly to devices with the corresponding bit NETIF_F_GSO_ROBUST. If the device doesn't have that bit, then the skb is fed to the GSO engine which will allow the packet to be sent to the hardware if it passes the header check. This patch changes the sg flag to a full features flag. The same method can be used to implement TSO ECN support. We simply have to mark packets with CWR set with SKB_GSO_ECN so that only hardware with a corresponding NETIF_F_TSO_ECN can accept them. The GSO engine can either fully segment the packet, or segment the first MTU and pass the rest to the hardware for further segmentation. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/bridge/br_device.c | 4 ++-- net/bridge/br_if.c | 3 ++- net/core/dev.c | 33 ++++++++++++++++++++++++--------- net/core/skbuff.c | 5 +++-- net/ipv4/af_inet.c | 6 +++--- net/ipv4/tcp.c | 8 ++++++-- 6 files changed, 40 insertions(+), 19 deletions(-) (limited to 'net') diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c index 2afdc7c0736c..f8dbcee80eba 100644 --- a/net/bridge/br_device.c +++ b/net/bridge/br_device.c @@ -184,6 +184,6 @@ void br_dev_setup(struct net_device *dev) dev->set_mac_address = br_set_mac_address; dev->priv_flags = IFF_EBRIDGE; - dev->features = NETIF_F_SG | NETIF_F_FRAGLIST - | NETIF_F_HIGHDMA | NETIF_F_TSO | NETIF_F_NO_CSUM; + dev->features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA | + NETIF_F_TSO | NETIF_F_NO_CSUM | NETIF_F_GSO_ROBUST; } diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c index 07956ecf545e..f55ef682ef84 100644 --- a/net/bridge/br_if.c +++ b/net/bridge/br_if.c @@ -392,7 +392,8 @@ void br_features_recompute(struct net_bridge *br) features &= feature; } - br->dev->features = features | checksum | NETIF_F_LLTX; + br->dev->features = features | checksum | NETIF_F_LLTX | + NETIF_F_GSO_ROBUST; } /* called with RTNL */ diff --git a/net/core/dev.c b/net/core/dev.c index f1c52cbd6ef7..4f2014994a84 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1190,11 +1190,14 @@ out: /** * skb_gso_segment - Perform segmentation on skb. * @skb: buffer to segment - * @sg: whether scatter-gather is supported on the target. + * @features: features for the output path (see dev->features) * * This function segments the given skb and returns a list of segments. + * + * It may return NULL if the skb requires no segmentation. This is + * only possible when GSO is used for verifying header integrity. */ -struct sk_buff *skb_gso_segment(struct sk_buff *skb, int sg) +struct sk_buff *skb_gso_segment(struct sk_buff *skb, int features) { struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT); struct packet_type *ptype; @@ -1210,12 +1213,14 @@ struct sk_buff *skb_gso_segment(struct sk_buff *skb, int sg) rcu_read_lock(); list_for_each_entry_rcu(ptype, &ptype_base[ntohs(type) & 15], list) { if (ptype->type == type && !ptype->dev && ptype->gso_segment) { - segs = ptype->gso_segment(skb, sg); + segs = ptype->gso_segment(skb, features); break; } } rcu_read_unlock(); + __skb_push(skb, skb->data - skb->mac.raw); + return segs; } @@ -1291,9 +1296,15 @@ static int dev_gso_segment(struct sk_buff *skb) { struct net_device *dev = skb->dev; struct sk_buff *segs; + int features = dev->features & ~(illegal_highdma(dev, skb) ? + NETIF_F_SG : 0); + + segs = skb_gso_segment(skb, features); + + /* Verifying header integrity only. */ + if (!segs) + return 0; - segs = skb_gso_segment(skb, dev->features & NETIF_F_SG && - !illegal_highdma(dev, skb)); if (unlikely(IS_ERR(segs))) return PTR_ERR(segs); @@ -1310,13 +1321,17 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev) if (netdev_nit) dev_queue_xmit_nit(skb, dev); - if (!netif_needs_gso(dev, skb)) - return dev->hard_start_xmit(skb, dev); + if (netif_needs_gso(dev, skb)) { + if (unlikely(dev_gso_segment(skb))) + goto out_kfree_skb; + if (skb->next) + goto gso; + } - if (unlikely(dev_gso_segment(skb))) - goto out_kfree_skb; + return dev->hard_start_xmit(skb, dev); } +gso: do { struct sk_buff *nskb = skb->next; int rc; diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 6edbb90cbcec..dfef9eece83e 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1848,13 +1848,13 @@ EXPORT_SYMBOL_GPL(skb_pull_rcsum); /** * skb_segment - Perform protocol segmentation on skb. * @skb: buffer to segment - * @sg: whether scatter-gather can be used for generated segments + * @features: features for the output path (see dev->features) * * This function performs segmentation on the given skb. It returns * the segment at the given position. It returns NULL if there are * no more segments to generate, or when an error is encountered. */ -struct sk_buff *skb_segment(struct sk_buff *skb, int sg) +struct sk_buff *skb_segment(struct sk_buff *skb, int features) { struct sk_buff *segs = NULL; struct sk_buff *tail = NULL; @@ -1863,6 +1863,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, int sg) unsigned int offset = doffset; unsigned int headroom; unsigned int len; + int sg = features & NETIF_F_SG; int nfrags = skb_shinfo(skb)->nr_frags; int err = -ENOMEM; int i = 0; diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 461216b47948..8d157157bf8e 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1097,7 +1097,7 @@ int inet_sk_rebuild_header(struct sock *sk) EXPORT_SYMBOL(inet_sk_rebuild_header); -static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int sg) +static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features) { struct sk_buff *segs = ERR_PTR(-EINVAL); struct iphdr *iph; @@ -1126,10 +1126,10 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int sg) rcu_read_lock(); ops = rcu_dereference(inet_protos[proto]); if (ops && ops->gso_segment) - segs = ops->gso_segment(skb, sg); + segs = ops->gso_segment(skb, features); rcu_read_unlock(); - if (IS_ERR(segs)) + if (!segs || unlikely(IS_ERR(segs))) goto out; skb = segs; diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index c04176be7ed1..0336422c88a0 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2145,7 +2145,7 @@ int compat_tcp_getsockopt(struct sock *sk, int level, int optname, EXPORT_SYMBOL(compat_tcp_getsockopt); #endif -struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int sg) +struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features) { struct sk_buff *segs = ERR_PTR(-EINVAL); struct tcphdr *th; @@ -2166,10 +2166,14 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int sg) if (!pskb_may_pull(skb, thlen)) goto out; + segs = NULL; + if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) + goto out; + oldlen = (u16)~skb->len; __skb_pull(skb, thlen); - segs = skb_segment(skb, sg); + segs = skb_segment(skb, features); if (IS_ERR(segs)) goto out; -- cgit v1.2.2