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net_sched: cls_flow: use skb_header_pointer()
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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 <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@davem330
Eric Dumazet authored and davem330 committed Oct 24, 2011
1 parent 59445b6 commit 859c201
Showing 1 changed file with 96 additions and 92 deletions.
188 changes: 96 additions & 92 deletions net/sched/cls_flow.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}
Expand Down Expand Up @@ -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; \
Expand All @@ -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):
Expand All @@ -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):
Expand All @@ -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)
Expand Down Expand Up @@ -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:
Expand All @@ -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:
Expand Down

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