sch_choke: use skb_header_pointer()

Remove the assumption that skb_get_rxhash() makes IP header and ports
linear, and use skb_header_pointer() instead in choke_match_flow()

This permits __skb_get_rxhash() to use skb_header_pointer() eventually.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 10 deletions

diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index 3422b25df9e4..061bcb744bbd 100644
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -152,15 +152,14 @@ static bool choke_match_flow(struct sk_buff *skb1,
 {
         int off1, off2, poff;
         const u32 *ports1, *ports2;
+        u32 _ports1, _ports2;
         u8 ip_proto;
         __u32 hash1;
 
         if (skb1->protocol != skb2->protocol)
                 return false;
 
-        /* Use hash value as quick check
-         * Assumes that __skb_get_rxhash makes IP header and ports linear
-         */
+        /* Use rxhash value as quick check */
         hash1 = skb_get_rxhash(skb1);
         if (!hash1 || hash1 != skb_get_rxhash(skb2))
                 return false;
@@ -172,10 +171,12 @@ static bool choke_match_flow(struct sk_buff *skb1,
         switch (skb1->protocol) {
         case __constant_htons(ETH_P_IP): {
                 const struct iphdr *ip1, *ip2;
+                struct iphdr _ip1, _ip2;
 
-                ip1 = (const struct iphdr *) (skb1->data + off1);
-                ip2 = (const struct iphdr *) (skb2->data + off2);
-
+                ip1 = skb_header_pointer(skb1, off1, sizeof(_ip1), &_ip1);
+                ip2 = skb_header_pointer(skb2, off2, sizeof(_ip2), &_ip2);
+                if (!ip1 || !ip2)
+                        return false;
                 ip_proto = ip1->protocol;
                 if (ip_proto != ip2->protocol ||
                     ip1->saddr != ip2->saddr || ip1->daddr != ip2->daddr)
@@ -190,9 +191,12 @@ static bool choke_match_flow(struct sk_buff *skb1,
 
         case __constant_htons(ETH_P_IPV6): {
                 const struct ipv6hdr *ip1, *ip2;
+                struct ipv6hdr _ip1, _ip2;
 
-                ip1 = (const struct ipv6hdr *) (skb1->data + off1);
-                ip2 = (const struct ipv6hdr *) (skb2->data + off2);
+                ip1 = skb_header_pointer(skb1, off1, sizeof(_ip1), &_ip1);
+                ip2 = skb_header_pointer(skb2, off2, sizeof(_ip2), &_ip2);
+                if (!ip1 || !ip2)
+                        return false;
 
                 ip_proto = ip1->nexthdr;
                 if (ip_proto != ip2->nexthdr ||
@@ -214,8 +218,11 @@ static bool choke_match_flow(struct sk_buff *skb1,
         off1 += poff;
         off2 += poff;
 
-        ports1 = (__force u32 *)(skb1->data + off1);
-        ports2 = (__force u32 *)(skb2->data + off2);
+        ports1 = skb_header_pointer(skb1, off1, sizeof(_ports1), &_ports1);
+        ports2 = skb_header_pointer(skb2, off2, sizeof(_ports2), &_ports2);
+        if (!ports1 || !ports2)
+                return false;
+
         return *ports1 == *ports2;
 }