[PATCH net-next v3 1/3] flow_dissector: factor out the ports extraction in skb_flow_get_ports
From: Nikolay Aleksandrov <hidden>
Date: 2013-09-26 14:13:24
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Factor out the code that extracts the ports from skb_flow_dissect and
add a new function skb_flow_get_ports which can be re-used.
Suggested-by: Veaceslav Falico <redacted>
Signed-off-by: Nikolay Aleksandrov <redacted>
---
v2: new patch
v3: fix a bug in skb_flow_dissect where thoff didn't have poff added by
modifying thoff directly in skb_flow_get_ports as it's done anyway.
Also add the necessary export symbol for skb_flow_get_ports.
This seems like a good idea because there're other users that can re-use
it later as well.
include/net/flow_keys.h | 1 +
net/core/flow_dissector.c | 41 ++++++++++++++++++++++++++++++-----------
2 files changed, 31 insertions(+), 11 deletions(-)
diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h
index ac2439d..4db84ae 100644
--- a/include/net/flow_keys.h
+++ b/include/net/flow_keys.h@@ -14,4 +14,5 @@ struct flow_keys { }; bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow); +__be32 skb_flow_get_ports(const struct sk_buff *skb, int *thoff, u8 ip_proto); #endif
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 1929af8..7785398 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c@@ -25,9 +25,37 @@ static void iph_to_flow_copy_addrs(struct flow_keys *flow, const struct iphdr *i memcpy(&flow->src, &iph->saddr, sizeof(flow->src) + sizeof(flow->dst)); } +/** + * skb_flow_get_ports - extract the upper layer ports and return them + * @skb: buffer to extract the ports from + * @thoff: pointer to transport header offset + * @ip_proto: protocol for which to get port offset + * + * The function will try to retrieve the ports at offset thoff + poff where poff + * is the protocol port offset returned from proto_ports_offset, and if poff is + * more than or equal to 0 it'll add it to the value at the thoff address + */ +__be32 skb_flow_get_ports(const struct sk_buff *skb, int *thoff, u8 ip_proto) +{ + int poff = proto_ports_offset(ip_proto); + + if (poff >= 0) { + __be32 *ports, _ports; + + *thoff += poff; + ports = skb_header_pointer(skb, *thoff, sizeof(_ports), + &_ports); + if (ports) + return *ports; + } + + return 0; +} +EXPORT_SYMBOL(skb_flow_get_ports); + bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow) { - int poff, nhoff = skb_network_offset(skb); + int nhoff = skb_network_offset(skb); u8 ip_proto; __be16 proto = skb->protocol;
@@ -150,16 +178,7 @@ ipv6: } flow->ip_proto = ip_proto; - poff = proto_ports_offset(ip_proto); - if (poff >= 0) { - __be32 *ports, _ports; - - nhoff += poff; - ports = skb_header_pointer(skb, nhoff, sizeof(_ports), &_ports); - if (ports) - flow->ports = *ports; - } - + flow->ports = skb_flow_get_ports(skb, &nhoff, ip_proto); flow->thoff = (u16) nhoff; return true;
--
1.8.1.4