[NET] gso: Fix up GSO packets with broken checksums

Certain subsystems in the stack (e.g., netfilter) can break the partial
checksum on GSO packets.  Until they're fixed, this patch allows this to
work by recomputing the partial checksums through the GSO mechanism.

Once they've all been converted to update the partial checksum instead of
clearing it, this workaround can be removed.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0359a6430018ed62b07d8a2cb6e5cc2876b32f9f..76cc099c8580fa06551f98f0ec2635f2c2a85496 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -549,6 +549,7 @@ struct packet_type {
                                         struct net_device *);
        struct sk_buff          *(*gso_segment)(struct sk_buff *skb,
                                                int features);
+       int                     (*gso_send_check)(struct sk_buff *skb);
        void                    *af_packet_priv;
        struct list_head        list;
 };
@@ -1001,13 +1002,14 @@ static inline int net_gso_ok(int features, int gso_type)
 
 static inline int skb_gso_ok(struct sk_buff *skb, int features)
 {
-       return net_gso_ok(features, skb_is_gso(skb) ?
-                                   skb_shinfo(skb)->gso_type : 0);
+       return net_gso_ok(features, skb_shinfo(skb)->gso_type);
 }
 
 static inline int netif_needs_gso(struct net_device *dev, struct sk_buff *skb)
 {
-       return !skb_gso_ok(skb, dev->features);
+       return skb_is_gso(skb) &&
+              (!skb_gso_ok(skb, dev->features) ||
+               unlikely(skb->ip_summed != CHECKSUM_HW));
 }
 
 #endif /* __KERNEL__ */

diff --git a/include/net/protocol.h b/include/net/protocol.h
index a225d6371cb12f5d5efa6b4318d1a54004c4bc01..c643bce64e552d0789facb53ebec5697e3ecd88b 100644 (file)
--- a/include/net/protocol.h
+++ b/include/net/protocol.h
@@ -36,6 +36,7 @@
 struct net_protocol {
        int                     (*handler)(struct sk_buff *skb);
        void                    (*err_handler)(struct sk_buff *skb, u32 info);
+       int                     (*gso_send_check)(struct sk_buff *skb);
        struct sk_buff         *(*gso_segment)(struct sk_buff *skb,
                                               int features);
        int                     no_policy;
@@ -51,6 +52,7 @@ struct inet6_protocol
                               int type, int code, int offset,
                               __u32 info);
 
+       int     (*gso_send_check)(struct sk_buff *skb);
        struct sk_buff *(*gso_segment)(struct sk_buff *skb,
                                       int features);
 

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 3cd803b0d7a531537961483aec4ea77923b8d418..0720bddff1e9cee11ac9f176b4ef2d59c1356ded 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1086,6 +1086,7 @@ extern struct request_sock_ops tcp_request_sock_ops;
 
 extern int tcp_v4_destroy_sock(struct sock *sk);
 
+extern int tcp_v4_gso_send_check(struct sk_buff *skb);
 extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features);
 
 #ifdef CONFIG_PROC_FS

diff --git a/net/core/dev.c b/net/core/dev.c
index 0096349ee38ba7b4d2c0f5f2370395daf0cb2bc1..4d2b5167d7f5f7b3088d1b12d7d7f5e2945fb11a 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1162,9 +1162,17 @@ int skb_checksum_help(struct sk_buff *skb, int inward)
        unsigned int csum;
        int ret = 0, offset = skb->h.raw - skb->data;
 
-       if (inward) {
-               skb->ip_summed = CHECKSUM_NONE;
-               goto out;
+       if (inward)
+               goto out_set_summed;
+
+       if (unlikely(skb_shinfo(skb)->gso_size)) {
+               static int warned;
+
+               WARN_ON(!warned);
+               warned = 1;
+
+               /* Let GSO fix up the checksum. */
+               goto out_set_summed;
        }
 
        if (skb_cloned(skb)) {
@@ -1181,6 +1189,8 @@ int skb_checksum_help(struct sk_buff *skb, int inward)
        BUG_ON(skb->csum + 2 > offset);
 
        *(u16*)(skb->h.raw + skb->csum) = csum_fold(csum);
+
+out_set_summed:
        skb->ip_summed = CHECKSUM_NONE;
 out:   
        return ret;
@@ -1201,17 +1211,35 @@ struct sk_buff *skb_gso_segment(struct sk_buff *skb, int features)
        struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
        struct packet_type *ptype;
        int type = skb->protocol;
+       int err;
 
        BUG_ON(skb_shinfo(skb)->frag_list);
-       BUG_ON(skb->ip_summed != CHECKSUM_HW);
 
        skb->mac.raw = skb->data;
        skb->mac_len = skb->nh.raw - skb->data;
        __skb_pull(skb, skb->mac_len);
 
+       if (unlikely(skb->ip_summed != CHECKSUM_HW)) {
+               static int warned;
+
+               WARN_ON(!warned);
+               warned = 1;
+
+               if (skb_header_cloned(skb) &&
+                   (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+                       return ERR_PTR(err);
+       }
+
        rcu_read_lock();
        list_for_each_entry_rcu(ptype, &ptype_base[ntohs(type) & 15], list) {
                if (ptype->type == type && !ptype->dev && ptype->gso_segment) {
+                       if (unlikely(skb->ip_summed != CHECKSUM_HW)) {
+                               err = ptype->gso_send_check(skb);
+                               segs = ERR_PTR(err);
+                               if (err || skb_gso_ok(skb, features))
+                                       break;
+                               __skb_push(skb, skb->data - skb->nh.raw);
+                       }
                        segs = ptype->gso_segment(skb, features);
                        break;
                }

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 318d4674faa188e8aba6c6c8c17862fed6ce6ee6..c84a32070f8d0dc58ca797e8625942cda0f1d302 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1097,6 +1097,40 @@ int inet_sk_rebuild_header(struct sock *sk)
 
 EXPORT_SYMBOL(inet_sk_rebuild_header);
 
+static int inet_gso_send_check(struct sk_buff *skb)
+{
+       struct iphdr *iph;
+       struct net_protocol *ops;
+       int proto;
+       int ihl;
+       int err = -EINVAL;
+
+       if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
+               goto out;
+
+       iph = skb->nh.iph;
+       ihl = iph->ihl * 4;
+       if (ihl < sizeof(*iph))
+               goto out;
+
+       if (unlikely(!pskb_may_pull(skb, ihl)))
+               goto out;
+
+       skb->h.raw = __skb_pull(skb, ihl);
+       iph = skb->nh.iph;
+       proto = iph->protocol & (MAX_INET_PROTOS - 1);
+       err = -EPROTONOSUPPORT;
+
+       rcu_read_lock();
+       ops = rcu_dereference(inet_protos[proto]);
+       if (likely(ops && ops->gso_send_check))
+               err = ops->gso_send_check(skb);
+       rcu_read_unlock();
+
+out:
+       return err;
+}
+
 static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
 {
        struct sk_buff *segs = ERR_PTR(-EINVAL);
@@ -1162,6 +1196,7 @@ static struct net_protocol igmp_protocol = {
 static struct net_protocol tcp_protocol = {
        .handler =      tcp_v4_rcv,
        .err_handler =  tcp_v4_err,
+       .gso_send_check = tcp_v4_gso_send_check,
        .gso_segment =  tcp_tso_segment,
        .no_policy =    1,
 };
@@ -1208,6 +1243,7 @@ static int ipv4_proc_init(void);
 static struct packet_type ip_packet_type = {
        .type = __constant_htons(ETH_P_IP),
        .func = ip_rcv,
+       .gso_send_check = inet_gso_send_check,
        .gso_segment = inet_gso_segment,
 };
 

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 5a886e6efbbedfc79ba382d131fa70338b9138d6..a891133f00e48fa2bf3e17f7f938a810e1f07d29 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -496,6 +496,24 @@ void tcp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb)
        }
 }
 
+int tcp_v4_gso_send_check(struct sk_buff *skb)
+{
+       struct iphdr *iph;
+       struct tcphdr *th;
+
+       if (!pskb_may_pull(skb, sizeof(*th)))
+               return -EINVAL;
+
+       iph = skb->nh.iph;
+       th = skb->h.th;
+
+       th->check = 0;
+       th->check = ~tcp_v4_check(th, skb->len, iph->saddr, iph->daddr, 0);
+       skb->csum = offsetof(struct tcphdr, check);
+       skb->ip_summed = CHECKSUM_HW;
+       return 0;
+}
+
 /*
  *     This routine will send an RST to the other tcp.
  *

diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 0c17dec11c8d1215725f780666056f8304ecf25f..43327264e69c4be3fadaa055adf0b0940fec717e 100644 (file)
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -57,29 +57,11 @@
 
 DEFINE_SNMP_STAT(struct ipstats_mib, ipv6_statistics) __read_mostly;
 
-static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
+static struct inet6_protocol *ipv6_gso_pull_exthdrs(struct sk_buff *skb,
+                                                   int proto)
 {
-       struct sk_buff *segs = ERR_PTR(-EINVAL);
-       struct ipv6hdr *ipv6h;
-       struct inet6_protocol *ops;
-       int proto;
+       struct inet6_protocol *ops = NULL;
 
-       if (unlikely(skb_shinfo(skb)->gso_type &
-                    ~(SKB_GSO_UDP |
-                      SKB_GSO_DODGY |
-                      SKB_GSO_TCP_ECN |
-                      SKB_GSO_TCPV6 |
-                      0)))
-               goto out;
-
-       if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
-               goto out;
-
-       ipv6h = skb->nh.ipv6h;
-       proto = ipv6h->nexthdr;
-       __skb_pull(skb, sizeof(*ipv6h));
-
-       rcu_read_lock();
        for (;;) {
                struct ipv6_opt_hdr *opth;
                int len;
@@ -88,30 +70,80 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
                        ops = rcu_dereference(inet6_protos[proto]);
 
                        if (unlikely(!ops))
-                               goto unlock;
+                               break;
 
                        if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
                                break;
                }
 
                if (unlikely(!pskb_may_pull(skb, 8)))
-                       goto unlock;
+                       break;
 
                opth = (void *)skb->data;
                len = opth->hdrlen * 8 + 8;
 
                if (unlikely(!pskb_may_pull(skb, len)))
-                       goto unlock;
+                       break;
 
                proto = opth->nexthdr;
                __skb_pull(skb, len);
        }
 
-       skb->h.raw = skb->data;
-       if (likely(ops->gso_segment))
-               segs = ops->gso_segment(skb, features);
+       return ops;
+}
+
+static int ipv6_gso_send_check(struct sk_buff *skb)
+{
+       struct ipv6hdr *ipv6h;
+       struct inet6_protocol *ops;
+       int err = -EINVAL;
+
+       if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
+               goto out;
 
-unlock:
+       ipv6h = skb->nh.ipv6h;
+       __skb_pull(skb, sizeof(*ipv6h));
+       err = -EPROTONOSUPPORT;
+
+       rcu_read_lock();
+       ops = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
+       if (likely(ops && ops->gso_send_check)) {
+               skb->h.raw = skb->data;
+               err = ops->gso_send_check(skb);
+       }
+       rcu_read_unlock();
+
+out:
+       return err;
+}
+
+static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
+{
+       struct sk_buff *segs = ERR_PTR(-EINVAL);
+       struct ipv6hdr *ipv6h;
+       struct inet6_protocol *ops;
+
+       if (unlikely(skb_shinfo(skb)->gso_type &
+                    ~(SKB_GSO_UDP |
+                      SKB_GSO_DODGY |
+                      SKB_GSO_TCP_ECN |
+                      SKB_GSO_TCPV6 |
+                      0)))
+               goto out;
+
+       if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
+               goto out;
+
+       ipv6h = skb->nh.ipv6h;
+       __skb_pull(skb, sizeof(*ipv6h));
+       segs = ERR_PTR(-EPROTONOSUPPORT);
+
+       rcu_read_lock();
+       ops = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
+       if (likely(ops && ops->gso_segment)) {
+               skb->h.raw = skb->data;
+               segs = ops->gso_segment(skb, features);
+       }
        rcu_read_unlock();
 
        if (unlikely(IS_ERR(segs)))
@@ -130,6 +162,7 @@ out:
 static struct packet_type ipv6_packet_type = {
        .type = __constant_htons(ETH_P_IPV6), 
        .func = ipv6_rcv,
+       .gso_send_check = ipv6_gso_send_check,
        .gso_segment = ipv6_gso_segment,
 };
 

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 5bdcb9002cf733ee670c05d12e2801e3a9488302..923989d0520d98f4527518b220b41442fcb84803 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -552,6 +552,24 @@ static void tcp_v6_send_check(struct sock *sk, int len, struct sk_buff *skb)
        }
 }
 
+static int tcp_v6_gso_send_check(struct sk_buff *skb)
+{
+       struct ipv6hdr *ipv6h;
+       struct tcphdr *th;
+
+       if (!pskb_may_pull(skb, sizeof(*th)))
+               return -EINVAL;
+
+       ipv6h = skb->nh.ipv6h;
+       th = skb->h.th;
+
+       th->check = 0;
+       th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
+                                    IPPROTO_TCP, 0);
+       skb->csum = offsetof(struct tcphdr, check);
+       skb->ip_summed = CHECKSUM_HW;
+       return 0;
+}
 
 static void tcp_v6_send_reset(struct sk_buff *skb)
 {
@@ -1603,6 +1621,7 @@ struct proto tcpv6_prot = {
 static struct inet6_protocol tcpv6_protocol = {
        .handler        =       tcp_v6_rcv,
        .err_handler    =       tcp_v6_err,
+       .gso_send_check =       tcp_v6_gso_send_check,
        .gso_segment    =       tcp_tso_segment,
        .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 };