10 files changed, 63 insertions, 24 deletions

diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h
index a734bf43d190..7cf272a4b5c8 100644
--- a/include/linux/netdev_features.h
+++ b/include/linux/netdev_features.h
@@ -39,6 +39,7 @@ enum {
         NETIF_F_UFO_BIT,                /* ... UDPv4 fragmentation */
         NETIF_F_GSO_ROBUST_BIT,         /* ... ->SKB_GSO_DODGY */
         NETIF_F_TSO_ECN_BIT,            /* ... TCP ECN support */
+        NETIF_F_TSO_MANGLEID_BIT,       /* ... IPV4 ID mangling allowed */
         NETIF_F_TSO6_BIT,               /* ... TCPv6 segmentation */
         NETIF_F_FSO_BIT,                /* ... FCoE segmentation */
         NETIF_F_GSO_GRE_BIT,            /* ... GRE with TSO */
@@ -120,6 +121,7 @@ enum {
 #define NETIF_F_GSO_SIT         __NETIF_F(GSO_SIT)
 #define NETIF_F_GSO_UDP_TUNNEL  __NETIF_F(GSO_UDP_TUNNEL)
 #define NETIF_F_GSO_UDP_TUNNEL_CSUM __NETIF_F(GSO_UDP_TUNNEL_CSUM)
+#define NETIF_F_TSO_MANGLEID    __NETIF_F(TSO_MANGLEID)
 #define NETIF_F_GSO_TUNNEL_REMCSUM __NETIF_F(GSO_TUNNEL_REMCSUM)
 #define NETIF_F_HW_VLAN_STAG_FILTER __NETIF_F(HW_VLAN_STAG_FILTER)
 #define NETIF_F_HW_VLAN_STAG_RX __NETIF_F(HW_VLAN_STAG_RX)
@@ -147,6 +149,7 @@ enum {
 
 /* List of features with software fallbacks. */
 #define NETIF_F_GSO_SOFTWARE    (NETIF_F_TSO | NETIF_F_TSO_ECN | \
+                                 NETIF_F_TSO_MANGLEID | \
                                  NETIF_F_TSO6 | NETIF_F_UFO)
 
 /* List of IP checksum features. Note that NETIF_F_ HW_CSUM should not be
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 9884fe9a6552..8e372d01b3c1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3992,6 +3992,7 @@ static inline bool net_gso_ok(netdev_features_t features, int gso_type)
         BUILD_BUG_ON(SKB_GSO_UDP     != (NETIF_F_UFO >> NETIF_F_GSO_SHIFT));
         BUILD_BUG_ON(SKB_GSO_DODGY   != (NETIF_F_GSO_ROBUST >> NETIF_F_GSO_SHIFT));
         BUILD_BUG_ON(SKB_GSO_TCP_ECN != (NETIF_F_TSO_ECN >> NETIF_F_GSO_SHIFT));
+        BUILD_BUG_ON(SKB_GSO_TCP_FIXEDID != (NETIF_F_TSO_MANGLEID >> NETIF_F_GSO_SHIFT));
         BUILD_BUG_ON(SKB_GSO_TCPV6   != (NETIF_F_TSO6 >> NETIF_F_GSO_SHIFT));
         BUILD_BUG_ON(SKB_GSO_FCOE    != (NETIF_F_FSO >> NETIF_F_GSO_SHIFT));
         BUILD_BUG_ON(SKB_GSO_GRE     != (NETIF_F_GSO_GRE >> NETIF_F_GSO_SHIFT));
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 007381270ff8..5fba16658f9d 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -465,23 +465,25 @@ enum {
         /* This indicates the tcp segment has CWR set. */
         SKB_GSO_TCP_ECN = 1 << 3,
 
-        SKB_GSO_TCPV6 = 1 << 4,
+        SKB_GSO_TCP_FIXEDID = 1 << 4,
 
-        SKB_GSO_FCOE = 1 << 5,
+        SKB_GSO_TCPV6 = 1 << 5,
 
-        SKB_GSO_GRE = 1 << 6,
+        SKB_GSO_FCOE = 1 << 6,
 
-        SKB_GSO_GRE_CSUM = 1 << 7,
+        SKB_GSO_GRE = 1 << 7,
 
-        SKB_GSO_IPIP = 1 << 8,
+        SKB_GSO_GRE_CSUM = 1 << 8,
 
-        SKB_GSO_SIT = 1 << 9,
+        SKB_GSO_IPIP = 1 << 9,
 
-        SKB_GSO_UDP_TUNNEL = 1 << 10,
+        SKB_GSO_SIT = 1 << 10,
 
-        SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11,
+        SKB_GSO_UDP_TUNNEL = 1 << 11,
 
-        SKB_GSO_TUNNEL_REMCSUM = 1 << 12,
+        SKB_GSO_UDP_TUNNEL_CSUM = 1 << 12,
+
+        SKB_GSO_TUNNEL_REMCSUM = 1 << 13,
 };
 
 #if BITS_PER_LONG > 32
diff --git a/net/core/dev.c b/net/core/dev.c
index 09fb1ace9dc8..e896b1953ab6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2825,14 +2825,36 @@ static netdev_features_t dflt_features_check(const struct sk_buff *skb,
         return vlan_features_check(skb, features);
 }
 
+static netdev_features_t gso_features_check(const struct sk_buff *skb,
+                                            struct net_device *dev,
+                                            netdev_features_t features)
+{
+        u16 gso_segs = skb_shinfo(skb)->gso_segs;
+
+        if (gso_segs > dev->gso_max_segs)
+                return features & ~NETIF_F_GSO_MASK;
+
+        /* Make sure to clear the IPv4 ID mangling feature if
+         * the IPv4 header has the potential to be fragmented.
+         */
+        if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) {
+                struct iphdr *iph = skb->encapsulation ?
+                                    inner_ip_hdr(skb) : ip_hdr(skb);
+
+                if (!(iph->frag_off & htons(IP_DF)))
+                        features &= ~NETIF_F_TSO_MANGLEID;
+        }
+
+        return features;
+}
+
 netdev_features_t netif_skb_features(struct sk_buff *skb)
 {
         struct net_device *dev = skb->dev;
         netdev_features_t features = dev->features;
-        u16 gso_segs = skb_shinfo(skb)->gso_segs;
 
-        if (gso_segs > dev->gso_max_segs)
-                features &= ~NETIF_F_GSO_MASK;
+        if (skb_is_gso(skb))
+                features = gso_features_check(skb, dev, features);
 
         /* If encapsulation offload request, verify we are testing
          * hardware encapsulation features instead of standard
@@ -6976,9 +6998,11 @@ int register_netdevice(struct net_device *dev)
         dev->features |= NETIF_F_SOFT_FEATURES;
         dev->wanted_features = dev->features & dev->hw_features;
 
-        if (!(dev->flags & IFF_LOOPBACK)) {
+        if (!(dev->flags & IFF_LOOPBACK))
                 dev->hw_features |= NETIF_F_NOCACHE_COPY;
-        }
+
+        if (dev->hw_features & NETIF_F_TSO)
+                dev->hw_features |= NETIF_F_TSO_MANGLEID;
 
         /* Make NETIF_F_HIGHDMA inheritable to VLAN devices.
          */
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 6a7f99661c2f..9494c41cc77c 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -79,6 +79,7 @@ static const char netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN]
         [NETIF_F_UFO_BIT] =              "tx-udp-fragmentation",
         [NETIF_F_GSO_ROBUST_BIT] =       "tx-gso-robust",
         [NETIF_F_TSO_ECN_BIT] =          "tx-tcp-ecn-segmentation",
+        [NETIF_F_TSO_MANGLEID_BIT] =     "tx-tcp-mangleid-segmentation",
         [NETIF_F_TSO6_BIT] =             "tx-tcp6-segmentation",
         [NETIF_F_FSO_BIT] =              "tx-fcoe-segmentation",
         [NETIF_F_GSO_GRE_BIT] =          "tx-gre-segmentation",
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 8217cd22f921..5bbea9a0ce96 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1195,10 +1195,10 @@ EXPORT_SYMBOL(inet_sk_rebuild_header);
 static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
                                         netdev_features_t features)
 {
+        bool udpfrag = false, fixedid = false, encap;
         struct sk_buff *segs = ERR_PTR(-EINVAL);
         const struct net_offload *ops;
         unsigned int offset = 0;
-        bool udpfrag, encap;
         struct iphdr *iph;
         int proto;
         int nhoff;
@@ -1217,6 +1217,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
                        SKB_GSO_TCPV6 |
                        SKB_GSO_UDP_TUNNEL |
                        SKB_GSO_UDP_TUNNEL_CSUM |
+                       SKB_GSO_TCP_FIXEDID |
                        SKB_GSO_TUNNEL_REMCSUM |
                        0)))
                 goto out;
@@ -1248,11 +1249,14 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
 
         segs = ERR_PTR(-EPROTONOSUPPORT);
 
-        if (skb->encapsulation &&
-            skb_shinfo(skb)->gso_type & (SKB_GSO_SIT|SKB_GSO_IPIP))
-                udpfrag = proto == IPPROTO_UDP && encap;
-        else
-                udpfrag = proto == IPPROTO_UDP && !skb->encapsulation;
+        if (!skb->encapsulation || encap) {
+                udpfrag = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
+                fixedid = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TCP_FIXEDID);
+
+                /* fixed ID is invalid if DF bit is not set */
+                if (fixedid && !(iph->frag_off & htons(IP_DF)))
+                        goto out;
+        }
 
         ops = rcu_dereference(inet_offloads[proto]);
         if (likely(ops && ops->callbacks.gso_segment))
@@ -1265,12 +1269,11 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
         do {
                 iph = (struct iphdr *)(skb_mac_header(skb) + nhoff);
                 if (udpfrag) {
-                        iph->id = htons(id);
                         iph->frag_off = htons(offset >> 3);
                         if (skb->next)
                                 iph->frag_off |= htons(IP_MF);
                         offset += skb->len - nhoff - ihl;
-                } else {
+                } else if (!fixedid) {
                         iph->id = htons(id++);
                 }
                 iph->tot_len = htons(skb->len - nhoff);
diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index 6a5bd4317866..6376b0cdf693 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -32,6 +32,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
                                   SKB_GSO_UDP |
                                   SKB_GSO_DODGY |
                                   SKB_GSO_TCP_ECN |
+                                  SKB_GSO_TCP_FIXEDID |
                                   SKB_GSO_GRE |
                                   SKB_GSO_GRE_CSUM |
                                   SKB_GSO_IPIP |
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index 773083b7f1e9..08dd25d835af 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -89,6 +89,7 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
                              ~(SKB_GSO_TCPV4 |
                                SKB_GSO_DODGY |
                                SKB_GSO_TCP_ECN |
+                               SKB_GSO_TCP_FIXEDID |
                                SKB_GSO_TCPV6 |
                                SKB_GSO_GRE |
                                SKB_GSO_GRE_CSUM |
@@ -98,7 +99,8 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
                                SKB_GSO_UDP_TUNNEL_CSUM |
                                SKB_GSO_TUNNEL_REMCSUM |
                                0) ||
-                             !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
+                             !(type & (SKB_GSO_TCPV4 |
+                                       SKB_GSO_TCPV6))))
                         goto out;
 
                 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index 204af2219471..b3a779393d71 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -73,6 +73,8 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
                        SKB_GSO_UDP |
                        SKB_GSO_DODGY |
                        SKB_GSO_TCP_ECN |
+                       SKB_GSO_TCP_FIXEDID |
+                       SKB_GSO_TCPV6 |
                        SKB_GSO_GRE |
                        SKB_GSO_GRE_CSUM |
                        SKB_GSO_IPIP |
@@ -80,7 +82,6 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
                        SKB_GSO_UDP_TUNNEL |
                        SKB_GSO_UDP_TUNNEL_CSUM |
                        SKB_GSO_TUNNEL_REMCSUM |
-                       SKB_GSO_TCPV6 |
                        0)))
                 goto out;
 
diff --git a/net/mpls/mpls_gso.c b/net/mpls/mpls_gso.c
index 0183b32da942..bbcf60465e5c 100644
--- a/net/mpls/mpls_gso.c
+++ b/net/mpls/mpls_gso.c
@@ -31,6 +31,7 @@ static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
                                   SKB_GSO_TCPV6 |
                                   SKB_GSO_UDP |
                                   SKB_GSO_DODGY |
+                                  SKB_GSO_TCP_FIXEDID |
                                   SKB_GSO_TCP_ECN)))
                 goto out;