From 859c20123a6f4bac3fad6506f224908834fe3f68 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 23 Oct 2011 17:59:41 +0000 Subject: [PATCH] net_sched: cls_flow: use skb_header_pointer() Dan Siemon would like to add tunnelling support to cls_flow This preliminary patch introduces use of skb_header_pointer() to help this task, while avoiding skb head reallocation because of deep packet inspection. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/cls_flow.c | 188 ++++++++++++++++++++++--------------------- 1 file changed, 96 insertions(+), 92 deletions(-) diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c index 6994214db8f8..9e087d885675 100644 --- a/net/sched/cls_flow.c +++ b/net/sched/cls_flow.c @@ -65,132 +65,134 @@ static inline u32 addr_fold(void *addr) return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0); } -static u32 flow_get_src(struct sk_buff *skb) +static u32 flow_get_src(const struct sk_buff *skb, int nhoff) { + __be32 *data = NULL, hdata; + switch (skb->protocol) { case htons(ETH_P_IP): - if (pskb_network_may_pull(skb, sizeof(struct iphdr))) - return ntohl(ip_hdr(skb)->saddr); + data = skb_header_pointer(skb, + nhoff + offsetof(struct iphdr, + saddr), + 4, &hdata); break; case htons(ETH_P_IPV6): - if (pskb_network_may_pull(skb, sizeof(struct ipv6hdr))) - return ntohl(ipv6_hdr(skb)->saddr.s6_addr32[3]); + data = skb_header_pointer(skb, + nhoff + offsetof(struct ipv6hdr, + saddr.s6_addr32[3]), + 4, &hdata); break; } + if (data) + return ntohl(*data); return addr_fold(skb->sk); } -static u32 flow_get_dst(struct sk_buff *skb) +static u32 flow_get_dst(const struct sk_buff *skb, int nhoff) { + __be32 *data = NULL, hdata; + switch (skb->protocol) { case htons(ETH_P_IP): - if (pskb_network_may_pull(skb, sizeof(struct iphdr))) - return ntohl(ip_hdr(skb)->daddr); + data = skb_header_pointer(skb, + nhoff + offsetof(struct iphdr, + daddr), + 4, &hdata); break; case htons(ETH_P_IPV6): - if (pskb_network_may_pull(skb, sizeof(struct ipv6hdr))) - return ntohl(ipv6_hdr(skb)->daddr.s6_addr32[3]); + data = skb_header_pointer(skb, + nhoff + offsetof(struct ipv6hdr, + daddr.s6_addr32[3]), + 4, &hdata); break; } + if (data) + return ntohl(*data); return addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol; } -static u32 flow_get_proto(struct sk_buff *skb) +static u32 flow_get_proto(const struct sk_buff *skb, int nhoff) { + __u8 *data = NULL, hdata; + switch (skb->protocol) { case htons(ETH_P_IP): - return pskb_network_may_pull(skb, sizeof(struct iphdr)) ? - ip_hdr(skb)->protocol : 0; + data = skb_header_pointer(skb, + nhoff + offsetof(struct iphdr, + protocol), + 1, &hdata); + break; case htons(ETH_P_IPV6): - return pskb_network_may_pull(skb, sizeof(struct ipv6hdr)) ? - ipv6_hdr(skb)->nexthdr : 0; - default: - return 0; + data = skb_header_pointer(skb, + nhoff + offsetof(struct ipv6hdr, + nexthdr), + 1, &hdata); + break; } + if (data) + return *data; + return 0; } -static u32 flow_get_proto_src(struct sk_buff *skb) +/* helper function to get either src or dst port */ +static __be16 *flow_get_proto_common(const struct sk_buff *skb, int nhoff, + __be16 *_port, int dst) { + __be16 *port = NULL; + int poff; + switch (skb->protocol) { case htons(ETH_P_IP): { - struct iphdr *iph; - int poff; + struct iphdr *iph, _iph; - if (!pskb_network_may_pull(skb, sizeof(*iph))) + iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); + if (!iph) break; - iph = ip_hdr(skb); if (ip_is_fragment(iph)) break; poff = proto_ports_offset(iph->protocol); - if (poff >= 0 && - pskb_network_may_pull(skb, iph->ihl * 4 + 2 + poff)) { - iph = ip_hdr(skb); - return ntohs(*(__be16 *)((void *)iph + iph->ihl * 4 + - poff)); - } + if (poff >= 0) + port = skb_header_pointer(skb, + nhoff + iph->ihl * 4 + poff + dst, + sizeof(*_port), _port); break; } case htons(ETH_P_IPV6): { - struct ipv6hdr *iph; - int poff; + struct ipv6hdr *iph, _iph; - if (!pskb_network_may_pull(skb, sizeof(*iph))) + iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); + if (!iph) break; - iph = ipv6_hdr(skb); poff = proto_ports_offset(iph->nexthdr); - if (poff >= 0 && - pskb_network_may_pull(skb, sizeof(*iph) + poff + 2)) { - iph = ipv6_hdr(skb); - return ntohs(*(__be16 *)((void *)iph + sizeof(*iph) + - poff)); - } + if (poff >= 0) + port = skb_header_pointer(skb, + nhoff + sizeof(*iph) + poff + dst, + sizeof(*_port), _port); break; } } - return addr_fold(skb->sk); + return port; } -static u32 flow_get_proto_dst(struct sk_buff *skb) +static u32 flow_get_proto_src(const struct sk_buff *skb, int nhoff) { - switch (skb->protocol) { - case htons(ETH_P_IP): { - struct iphdr *iph; - int poff; + __be16 _port, *port = flow_get_proto_common(skb, nhoff, &_port, 0); - if (!pskb_network_may_pull(skb, sizeof(*iph))) - break; - iph = ip_hdr(skb); - if (ip_is_fragment(iph)) - break; - poff = proto_ports_offset(iph->protocol); - if (poff >= 0 && - pskb_network_may_pull(skb, iph->ihl * 4 + 4 + poff)) { - iph = ip_hdr(skb); - return ntohs(*(__be16 *)((void *)iph + iph->ihl * 4 + - 2 + poff)); - } - break; - } - case htons(ETH_P_IPV6): { - struct ipv6hdr *iph; - int poff; + if (port) + return ntohs(*port); - if (!pskb_network_may_pull(skb, sizeof(*iph))) - break; - iph = ipv6_hdr(skb); - poff = proto_ports_offset(iph->nexthdr); - if (poff >= 0 && - pskb_network_may_pull(skb, sizeof(*iph) + poff + 4)) { - iph = ipv6_hdr(skb); - return ntohs(*(__be16 *)((void *)iph + sizeof(*iph) + - poff + 2)); - } - break; - } - } + return addr_fold(skb->sk); +} + +static u32 flow_get_proto_dst(const struct sk_buff *skb, int nhoff) +{ + __be16 _port, *port = flow_get_proto_common(skb, nhoff, &_port, 2); + + if (port) + return ntohs(*port); return addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol; } @@ -223,7 +225,7 @@ static u32 flow_get_nfct(const struct sk_buff *skb) #define CTTUPLE(skb, member) \ ({ \ enum ip_conntrack_info ctinfo; \ - struct nf_conn *ct = nf_ct_get(skb, &ctinfo); \ + const struct nf_conn *ct = nf_ct_get(skb, &ctinfo); \ if (ct == NULL) \ goto fallback; \ ct->tuplehash[CTINFO2DIR(ctinfo)].tuple.member; \ @@ -236,7 +238,7 @@ static u32 flow_get_nfct(const struct sk_buff *skb) }) #endif -static u32 flow_get_nfct_src(struct sk_buff *skb) +static u32 flow_get_nfct_src(const struct sk_buff *skb, int nhoff) { switch (skb->protocol) { case htons(ETH_P_IP): @@ -245,10 +247,10 @@ static u32 flow_get_nfct_src(struct sk_buff *skb) return ntohl(CTTUPLE(skb, src.u3.ip6[3])); } fallback: - return flow_get_src(skb); + return flow_get_src(skb, nhoff); } -static u32 flow_get_nfct_dst(struct sk_buff *skb) +static u32 flow_get_nfct_dst(const struct sk_buff *skb, int nhoff) { switch (skb->protocol) { case htons(ETH_P_IP): @@ -257,21 +259,21 @@ static u32 flow_get_nfct_dst(struct sk_buff *skb) return ntohl(CTTUPLE(skb, dst.u3.ip6[3])); } fallback: - return flow_get_dst(skb); + return flow_get_dst(skb, nhoff); } -static u32 flow_get_nfct_proto_src(struct sk_buff *skb) +static u32 flow_get_nfct_proto_src(const struct sk_buff *skb, int nhoff) { return ntohs(CTTUPLE(skb, src.u.all)); fallback: - return flow_get_proto_src(skb); + return flow_get_proto_src(skb, nhoff); } -static u32 flow_get_nfct_proto_dst(struct sk_buff *skb) +static u32 flow_get_nfct_proto_dst(const struct sk_buff *skb, int nhoff) { return ntohs(CTTUPLE(skb, dst.u.all)); fallback: - return flow_get_proto_dst(skb); + return flow_get_proto_dst(skb, nhoff); } static u32 flow_get_rtclassid(const struct sk_buff *skb) @@ -313,17 +315,19 @@ static u32 flow_get_rxhash(struct sk_buff *skb) static u32 flow_key_get(struct sk_buff *skb, int key) { + int nhoff = skb_network_offset(skb); + switch (key) { case FLOW_KEY_SRC: - return flow_get_src(skb); + return flow_get_src(skb, nhoff); case FLOW_KEY_DST: - return flow_get_dst(skb); + return flow_get_dst(skb, nhoff); case FLOW_KEY_PROTO: - return flow_get_proto(skb); + return flow_get_proto(skb, nhoff); case FLOW_KEY_PROTO_SRC: - return flow_get_proto_src(skb); + return flow_get_proto_src(skb, nhoff); case FLOW_KEY_PROTO_DST: - return flow_get_proto_dst(skb); + return flow_get_proto_dst(skb, nhoff); case FLOW_KEY_IIF: return flow_get_iif(skb); case FLOW_KEY_PRIORITY: @@ -333,13 +337,13 @@ static u32 flow_key_get(struct sk_buff *skb, int key) case FLOW_KEY_NFCT: return flow_get_nfct(skb); case FLOW_KEY_NFCT_SRC: - return flow_get_nfct_src(skb); + return flow_get_nfct_src(skb, nhoff); case FLOW_KEY_NFCT_DST: - return flow_get_nfct_dst(skb); + return flow_get_nfct_dst(skb, nhoff); case FLOW_KEY_NFCT_PROTO_SRC: - return flow_get_nfct_proto_src(skb); + return flow_get_nfct_proto_src(skb, nhoff); case FLOW_KEY_NFCT_PROTO_DST: - return flow_get_nfct_proto_dst(skb); + return flow_get_nfct_proto_dst(skb, nhoff); case FLOW_KEY_RTCLASSID: return flow_get_rtclassid(skb); case FLOW_KEY_SKUID: -- 2.20.1