From 0744dd00c1b1be99a25b62b1b48df440e82e57e0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 28 Nov 2011 05:22:18 +0000 Subject: net: introduce skb_flow_dissect() We use at least two flow dissectors in network stack, with known limitations and code duplication. Introduce skb_flow_dissect() to factorize this, highly inspired from existing dissector from __skb_get_rxhash() Note : We extensively use skb_header_pointer(), this permits us to not touch skb at all. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/flow_dissector.c | 134 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 net/core/flow_dissector.c (limited to 'net/core/flow_dissector.c') diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c new file mode 100644 index 000000000000..f0516d9280c3 --- /dev/null +++ b/net/core/flow_dissector.c @@ -0,0 +1,134 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include + + +bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow) +{ + int poff, nhoff = skb_network_offset(skb); + u8 ip_proto; + __be16 proto = skb->protocol; + + memset(flow, 0, sizeof(*flow)); + +again: + switch (proto) { + case __constant_htons(ETH_P_IP): { + const struct iphdr *iph; + struct iphdr _iph; +ip: + iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); + if (!iph) + return false; + + if (ip_is_fragment(iph)) + ip_proto = 0; + else + ip_proto = iph->protocol; + flow->src = iph->saddr; + flow->dst = iph->daddr; + nhoff += iph->ihl * 4; + break; + } + case __constant_htons(ETH_P_IPV6): { + const struct ipv6hdr *iph; + struct ipv6hdr _iph; +ipv6: + iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); + if (!iph) + return false; + + ip_proto = iph->nexthdr; + flow->src = iph->saddr.s6_addr32[3]; + flow->dst = iph->daddr.s6_addr32[3]; + nhoff += sizeof(struct ipv6hdr); + break; + } + case __constant_htons(ETH_P_8021Q): { + const struct vlan_hdr *vlan; + struct vlan_hdr _vlan; + + vlan = skb_header_pointer(skb, nhoff, sizeof(_vlan), &_vlan); + if (!vlan) + return false; + + proto = vlan->h_vlan_encapsulated_proto; + nhoff += sizeof(*vlan); + goto again; + } + case __constant_htons(ETH_P_PPP_SES): { + struct { + struct pppoe_hdr hdr; + __be16 proto; + } *hdr, _hdr; + hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr); + if (!hdr) + return false; + proto = hdr->proto; + nhoff += PPPOE_SES_HLEN; + switch (proto) { + case __constant_htons(PPP_IP): + goto ip; + case __constant_htons(PPP_IPV6): + goto ipv6; + default: + return false; + } + } + default: + return false; + } + + switch (ip_proto) { + case IPPROTO_GRE: { + struct gre_hdr { + __be16 flags; + __be16 proto; + } *hdr, _hdr; + + hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr); + if (!hdr) + return false; + /* + * Only look inside GRE if version zero and no + * routing + */ + if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) { + proto = hdr->proto; + nhoff += 4; + if (hdr->flags & GRE_CSUM) + nhoff += 4; + if (hdr->flags & GRE_KEY) + nhoff += 4; + if (hdr->flags & GRE_SEQ) + nhoff += 4; + goto again; + } + break; + } + case IPPROTO_IPIP: + goto again; + default: + break; + } + + 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; + } + + return true; +} +EXPORT_SYMBOL(skb_flow_dissect); -- cgit v1.2.3-70-g09d2 From 4d77d2b567ec66a443792d99e96ac760991d80d0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 28 Nov 2011 20:30:35 +0000 Subject: flow_dissector: use a 64bit load/store MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Le lundi 28 novembre 2011 à 19:06 -0500, David Miller a écrit : > From: Dimitris Michailidis > Date: Mon, 28 Nov 2011 08:25:39 -0800 > > >> +bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys > >> *flow) > >> +{ > >> + int poff, nhoff = skb_network_offset(skb); > >> + u8 ip_proto; > >> + u16 proto = skb->protocol; > > > > __be16 instead of u16 for proto? > > I'll take care of this when I apply these patches. ( CC trimmed ) Thanks David ! Here is a small patch to use one 64bit load/store on x86_64 instead of two 32bit load/stores. [PATCH net-next] flow_dissector: use a 64bit load/store gcc compiler is smart enough to use a single load/store if we memcpy(dptr, sptr, 8) on x86_64, regardless of CONFIG_CC_OPTIMIZE_FOR_SIZE In IP header, daddr immediately follows saddr, this wont change in the future. We only need to make sure our flow_keys (src,dst) fields wont break the rule. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/flow_keys.h | 1 + net/core/flow_dissector.c | 13 +++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-) (limited to 'net/core/flow_dissector.c') diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h index e4cb28526563..80461c1ae9ef 100644 --- a/include/net/flow_keys.h +++ b/include/net/flow_keys.h @@ -2,6 +2,7 @@ #define _NET_FLOW_KEYS_H struct flow_keys { + /* (src,dst) must be grouped, in the same way than in IP header */ __be32 src; __be32 dst; union { diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index f0516d9280c3..0985b9b14b80 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -8,6 +8,16 @@ #include #include +/* copy saddr & daddr, possibly using 64bit load/store + * Equivalent to : flow->src = iph->saddr; + * flow->dst = iph->daddr; + */ +static void iph_to_flow_copy_addrs(struct flow_keys *flow, const struct iphdr *iph) +{ + BUILD_BUG_ON(offsetof(typeof(*flow), dst) != + offsetof(typeof(*flow), src) + sizeof(flow->src)); + memcpy(&flow->src, &iph->saddr, sizeof(flow->src) + sizeof(flow->dst)); +} bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow) { @@ -31,8 +41,7 @@ ip: ip_proto = 0; else ip_proto = iph->protocol; - flow->src = iph->saddr; - flow->dst = iph->daddr; + iph_to_flow_copy_addrs(flow, iph); nhoff += iph->ihl * 4; break; } -- cgit v1.2.3-70-g09d2 From c452ed70771cea3af73d21a5914989137fbd28b8 Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Tue, 24 Jan 2012 16:03:33 -0500 Subject: net: flow_dissector.c missing include linux/export.h The file net/core/flow_dissector.c seems to be missing including linux/export.h. Signed-off-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller --- net/core/flow_dissector.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/core/flow_dissector.c') diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 0985b9b14b80..a225089df5b6 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1,4 +1,5 @@ #include +#include #include #include #include -- cgit v1.2.3-70-g09d2