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>

diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index 3422b25df9e46d8149ea0591ddc1625740b64bb6..061bcb744bbd3852df7e8c5df6c01293156afad2 100644 (file)
--- 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;
 }