Merge branch 'inet_csums_part2'

Tom Herbert says:

====================
net: Checksum offload changes - Part II

I am working on overhauling RX checksum offload. Goals of this effort
are:

- Specify what exactly it means when driver returns CHECKSUM_UNNECESSARY
- Preserve CHECKSUM_COMPLETE through encapsulation layers
- Don't do skb_checksum more than once per packet
- Unify GRO and non-GRO csum verification as much as possible
- Unify the checksum functions (checksum_init)
- Simply code

What is in this second patch set:

- Call common inet checksum validation functions in ICMP{4,6},
  GRE{4,6}, and IGMP.
- In UDP, verify checksum before handing off to encap_rcv.
- Remove custom UDP checksum validation code in L2TP.

Please review carefully and test if possible, mucking with basic
checksum functions is always a little precarious :-)
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c
index 250be7421ab36c50ce00a25dcd3c659ca1c97f18..fbfd829f4049a36d1d3d590ec5d913785740fb24 100644 (file)
--- a/net/ipv4/gre_demux.c
+++ b/net/ipv4/gre_demux.c
@@ -93,28 +93,6 @@ void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 }
 EXPORT_SYMBOL_GPL(gre_build_header);
 
-static __sum16 check_checksum(struct sk_buff *skb)
-{
-       __sum16 csum = 0;
-
-       switch (skb->ip_summed) {
-       case CHECKSUM_COMPLETE:
-               csum = csum_fold(skb->csum);
-
-               if (!csum)
-                       break;
-               /* Fall through. */
-
-       case CHECKSUM_NONE:
-               skb->csum = 0;
-               csum = __skb_checksum_complete(skb);
-               skb->ip_summed = CHECKSUM_COMPLETE;
-               break;
-       }
-
-       return csum;
-}
-
 static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
                            bool *csum_err)
 {
@@ -141,7 +119,7 @@ static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 
        options = (__be32 *)(greh + 1);
        if (greh->flags & GRE_CSUM) {
-               if (check_checksum(skb)) {
+               if (skb_checksum_simple_validate(skb)) {
                        *csum_err = true;
                        return -EINVAL;
                }

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 0134663fdbce86f6da39d8f6c9d27ce6c404687c..fe52666dc43c9b3b6f03ecce294df1e88e4ca01c 100644 (file)
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -908,16 +908,8 @@ int icmp_rcv(struct sk_buff *skb)
 
        ICMP_INC_STATS_BH(net, ICMP_MIB_INMSGS);
 
-       switch (skb->ip_summed) {
-       case CHECKSUM_COMPLETE:
-               if (!csum_fold(skb->csum))
-                       break;
-               /* fall through */
-       case CHECKSUM_NONE:
-               skb->csum = 0;
-               if (__skb_checksum_complete(skb))
-                       goto csum_error;
-       }
+       if (skb_checksum_simple_validate(skb))
+               goto csum_error;
 
        if (!pskb_pull(skb, sizeof(*icmph)))
                goto error;

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 97e4d1655d26bb65121c1a8954af2d7565c288a6..17d34e3c2ac34f326cf68d74e4c7193f6d86d8e6 100644 (file)
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -988,16 +988,8 @@ int igmp_rcv(struct sk_buff *skb)
        if (!pskb_may_pull(skb, sizeof(struct igmphdr)))
                goto drop;
 
-       switch (skb->ip_summed) {
-       case CHECKSUM_COMPLETE:
-               if (!csum_fold(skb->csum))
-                       break;
-               /* fall through */
-       case CHECKSUM_NONE:
-               skb->csum = 0;
-               if (__skb_checksum_complete(skb))
-                       goto drop;
-       }
+       if (skb_checksum_simple_validate(skb))
+               goto drop;
 
        ih = igmp_hdr(skb);
        switch (ih->type) {

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index f2d05d7be743d09fd42cd0e302f4c088bc71048b..54ea0a3a48f17769cf1c78f40ce138a93808e75a 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1495,6 +1495,10 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
                if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
                        int ret;
 
+                       /* Verify checksum before giving to encap */
+                       if (udp_lib_checksum_complete(skb))
+                               goto csum_error;
+
                        ret = encap_rcv(sk, skb);
                        if (ret <= 0) {
                                UDP_INC_STATS_BH(sock_net(sk),

diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 3b0905b77127d9efb29e93f1fdcb432b5357fc97..8d3952796d39ec050fa25080cce1aa5fb3b5e82f 100644 (file)
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -692,22 +692,11 @@ static int icmpv6_rcv(struct sk_buff *skb)
        saddr = &ipv6_hdr(skb)->saddr;
        daddr = &ipv6_hdr(skb)->daddr;
 
-       /* Perform checksum. */
-       switch (skb->ip_summed) {
-       case CHECKSUM_COMPLETE:
-               if (!csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_ICMPV6,
-                                    skb->csum))
-                       break;
-               /* fall through */
-       case CHECKSUM_NONE:
-               skb->csum = ~csum_unfold(csum_ipv6_magic(saddr, daddr, skb->len,
-                                            IPPROTO_ICMPV6, 0));
-               if (__skb_checksum_complete(skb)) {
-                       LIMIT_NETDEBUG(KERN_DEBUG
-                                      "ICMPv6 checksum failed [%pI6c > %pI6c]\n",
-                                      saddr, daddr);
-                       goto csum_error;
-               }
+       if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) {
+               LIMIT_NETDEBUG(KERN_DEBUG
+                              "ICMPv6 checksum failed [%pI6c > %pI6c]\n",
+                              saddr, daddr);
+               goto csum_error;
        }
 
        if (!pskb_pull(skb, sizeof(*hdr)))

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 75277b739b0424eab8ef83081b1e7756966f2877..3873181ed85614a28f9857d7d53acf2be9d2b9fb 100644 (file)
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -468,17 +468,7 @@ static int ip6gre_rcv(struct sk_buff *skb)
                        goto drop;
 
                if (flags&GRE_CSUM) {
-                       switch (skb->ip_summed) {
-                       case CHECKSUM_COMPLETE:
-                               csum = csum_fold(skb->csum);
-                               if (!csum)
-                                       break;
-                               /* fall through */
-                       case CHECKSUM_NONE:
-                               skb->csum = 0;
-                               csum = __skb_checksum_complete(skb);
-                               skb->ip_summed = CHECKSUM_COMPLETE;
-                       }
+                       csum = skb_checksum_simple_validate(skb);
                        offset += 4;
                }
                if (flags&GRE_KEY) {

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index fc2be63e32d586d2b192314a7609c9e515ee7ddd..7edf096867c4205342152ea8a5fba6f7ad9a4a66 100644 (file)
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -634,6 +634,10 @@ int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
                if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
                        int ret;
 
+                       /* Verify checksum before giving to encap */
+                       if (udp_lib_checksum_complete(skb))
+                               goto csum_error;
+
                        ret = encap_rcv(sk, skb);
                        if (ret <= 0) {
                                UDP_INC_STATS_BH(sock_net(sk),

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index a4e37d7158dcca42455a04eaf0460a48e39242fd..aa1a9d44c107fd0bd446de521adbc2f2d16328a9 100644 (file)
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -495,52 +495,6 @@ out:
        spin_unlock_bh(&session->reorder_q.lock);
 }
 
-static inline int l2tp_verify_udp_checksum(struct sock *sk,
-                                          struct sk_buff *skb)
-{
-       struct udphdr *uh = udp_hdr(skb);
-       u16 ulen = ntohs(uh->len);
-       __wsum psum;
-
-       if (sk->sk_no_check || skb_csum_unnecessary(skb))
-               return 0;
-
-#if IS_ENABLED(CONFIG_IPV6)
-       if (sk->sk_family == PF_INET6 && !l2tp_tunnel(sk)->v4mapped) {
-               if (!uh->check) {
-                       LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n");
-                       return 1;
-               }
-               if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
-                   !csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
-                                    &ipv6_hdr(skb)->daddr, ulen,
-                                    IPPROTO_UDP, skb->csum)) {
-                       skb->ip_summed = CHECKSUM_UNNECESSARY;
-                       return 0;
-               }
-               skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
-                                                        &ipv6_hdr(skb)->daddr,
-                                                        skb->len, IPPROTO_UDP,
-                                                        0));
-       } else
-#endif
-       {
-               struct inet_sock *inet;
-               if (!uh->check)
-                       return 0;
-               inet = inet_sk(sk);
-               psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr,
-                                         ulen, IPPROTO_UDP, 0);
-
-               if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
-                   !csum_fold(csum_add(psum, skb->csum)))
-                       return 0;
-               skb->csum = psum;
-       }
-
-       return __skb_checksum_complete(skb);
-}
-
 static int l2tp_seq_check_rx_window(struct l2tp_session *session, u32 nr)
 {
        u32 nws;
@@ -895,8 +849,7 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
        u16 version;
        int length;
 
-       if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
-               goto discard_bad_csum;
+       /* UDP has verifed checksum */
 
        /* UDP always verifies the packet length. */
        __skb_pull(skb, sizeof(struct udphdr));
@@ -979,14 +932,6 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
 
        return 0;
 
-discard_bad_csum:
-       LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
-       UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
-       atomic_long_inc(&tunnel->stats.rx_errors);
-       kfree_skb(skb);
-
-       return 0;
-
 error:
        /* Put UDP header back */
        __skb_push(skb, sizeof(struct udphdr));