flow_dissector: Jump to exit code in __skb_flow_dissect

Instead of returning immediately (on a parsing failure for instance) we
jump to cleanup code. This always sets protocol values in key_control
(even on a failure there is still valid information in the key_tags that
was set before the problem was hit).

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 151b6e4..22f3d76 100644 (file)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -130,6 +130,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
        struct flow_dissector_key_tags *key_tags;
        struct flow_dissector_key_keyid *key_keyid;
        u8 ip_proto = 0;
+       bool ret = false;
 
        if (!data) {
                data = skb->data;
@@ -171,7 +172,7 @@ again:
 ip:
                iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
                if (!iph || iph->ihl < 5)
-                       return false;
+                       goto out_bad;
                nhoff += iph->ihl * 4;
 
                ip_proto = iph->protocol;
@@ -197,7 +198,7 @@ ip:
 ipv6:
                iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
                if (!iph)
-                       return false;
+                       goto out_bad;
 
                ip_proto = iph->nexthdr;
                nhoff += sizeof(struct ipv6hdr);
@@ -234,7 +235,7 @@ ipv6:
 
                vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), data, hlen, &_vlan);
                if (!vlan)
-                       return false;
+                       goto out_bad;
 
                if (skb_flow_dissector_uses_key(flow_dissector,
                                                FLOW_DISSECTOR_KEY_VLANID)) {
@@ -256,7 +257,7 @@ ipv6:
                } *hdr, _hdr;
                hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
                if (!hdr)
-                       return false;
+                       goto out_bad;
                proto = hdr->proto;
                nhoff += PPPOE_SES_HLEN;
                switch (proto) {
@@ -265,7 +266,7 @@ ipv6:
                case htons(PPP_IPV6):
                        goto ipv6;
                default:
-                       return false;
+                       goto out_bad;
                }
        }
        case htons(ETH_P_TIPC): {
@@ -275,9 +276,7 @@ ipv6:
                } *hdr, _hdr;
                hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
                if (!hdr)
-                       return false;
-               key_basic->n_proto = proto;
-               key_control->thoff = (u16)nhoff;
+                       goto out_bad;
 
                if (skb_flow_dissector_uses_key(flow_dissector,
                                                FLOW_DISSECTOR_KEY_TIPC_ADDRS)) {
@@ -287,7 +286,7 @@ ipv6:
                        key_addrs->tipcaddrs.srcnode = hdr->srcnode;
                        key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC_ADDRS;
                }
-               return true;
+               goto out_good;
        }
 
        case htons(ETH_P_MPLS_UC):
@@ -297,7 +296,7 @@ mpls:
                hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
                                           hlen, &_hdr);
                if (!hdr)
-                       return false;
+                       goto out_bad;
 
                if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) >>
                     MPLS_LS_LABEL_SHIFT == MPLS_LABEL_ENTROPY) {
@@ -310,21 +309,17 @@ mpls:
                                        htonl(MPLS_LS_LABEL_MASK);
                        }
 
-                       key_basic->n_proto = proto;
-                       key_basic->ip_proto = ip_proto;
-                       key_control->thoff = (u16)nhoff;
-
-                       return true;
+                       goto out_good;
                }
 
-               return true;
+               goto out_good;
        }
 
        case htons(ETH_P_FCOE):
                key_control->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
                /* fall through */
        default:
-               return false;
+               goto out_bad;
        }
 
 ip_proto_again:
@@ -337,7 +332,7 @@ ip_proto_again:
 
                hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
                if (!hdr)
-                       return false;
+                       goto out_bad;
                /*
                 * Only look inside GRE if version zero and no
                 * routing
@@ -357,7 +352,7 @@ ip_proto_again:
                                                     data, hlen, &_keyid);
 
                        if (!keyid)
-                               return false;
+                               goto out_bad;
 
                        if (skb_flow_dissector_uses_key(flow_dissector,
                                                        FLOW_DISSECTOR_KEY_GRE_KEYID)) {
@@ -378,7 +373,7 @@ ip_proto_again:
                                                   sizeof(_eth),
                                                   data, hlen, &_eth);
                        if (!eth)
-                               return false;
+                               goto out_bad;
                        proto = eth->h_proto;
                        nhoff += sizeof(*eth);
                }
@@ -395,7 +390,7 @@ ip_proto_again:
                opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr),
                                              data, hlen, &_opthdr);
                if (!opthdr)
-                       return false;
+                       goto out_bad;
 
                ip_proto = opthdr[0];
                nhoff += (opthdr[1] + 1) << 3;
@@ -415,10 +410,6 @@ ip_proto_again:
                break;
        }
 
-       key_basic->n_proto = proto;
-       key_basic->ip_proto = ip_proto;
-       key_control->thoff = (u16)nhoff;
-
        if (skb_flow_dissector_uses_key(flow_dissector,
                                        FLOW_DISSECTOR_KEY_PORTS)) {
                key_ports = skb_flow_dissector_target(flow_dissector,
@@ -428,7 +419,15 @@ ip_proto_again:
                                                        data, hlen);
        }
 
-       return true;
+out_good:
+       ret = true;
+
+out_bad:
+       key_basic->n_proto = proto;
+       key_basic->ip_proto = ip_proto;
+       key_control->thoff = (u16)nhoff;
+
+       return ret;
 }
 EXPORT_SYMBOL(__skb_flow_dissect);