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Avoid full checksum calculation for apps that can provide
info whether csum was broken after payload mangling. For now only
ip_vs_ftp mangles payload and it updates the csum, so the full
recalculation is avoided for all packets.
Add CHECKSUM_UNNECESSARY for snat_handler (TCP and UDP).
It is needed to support SNAT from local address for the case
when csum is fully recalculated.
Signed-off-by: Julian Anastasov <ja@xxxxxx>
---
diff -urp nf-next-2.6-a91fd26/linux/include/net/ip_vs.h
linux/include/net/ip_vs.h
--- nf-next-2.6-a91fd26/linux/include/net/ip_vs.h 2010-10-13
22:22:35.000000000 +0300
+++ linux/include/net/ip_vs.h 2010-10-16 12:46:47.934355392 +0300
@@ -593,11 +593,19 @@ struct ip_vs_app {
__be16 port; /* port number in net order */
atomic_t usecnt; /* usage counter */
- /* output hook: return false if can't linearize. diff set for TCP. */
+ /*
+ * output hook: Process packet in inout direction, diff set for TCP.
+ * Return: 0=Error, 1=Payload Not Mangled/Mangled but checksum is ok,
+ * 2=Mangled but checksum was not updated
+ */
int (*pkt_out)(struct ip_vs_app *, struct ip_vs_conn *,
struct sk_buff *, int *diff);
- /* input hook: return false if can't linearize. diff set for TCP. */
+ /*
+ * input hook: Process packet in outin direction, diff set for TCP.
+ * Return: 0=Error, 1=Payload Not Mangled/Mangled but checksum is ok,
+ * 2=Mangled but checksum was not updated
+ */
int (*pkt_in)(struct ip_vs_app *, struct ip_vs_conn *,
struct sk_buff *, int *diff);
diff -urp nf-next-2.6-a91fd26/linux/net/netfilter/ipvs/ip_vs_ftp.c
linux/net/netfilter/ipvs/ip_vs_ftp.c
--- nf-next-2.6-a91fd26/linux/net/netfilter/ipvs/ip_vs_ftp.c 2010-10-13
22:22:35.000000000 +0300
+++ linux/net/netfilter/ipvs/ip_vs_ftp.c 2010-10-16 12:46:47.934355392
+0300
@@ -242,9 +242,14 @@ static int ip_vs_ftp_out(struct ip_vs_ap
ret = nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
start-data, end-start,
buf, buf_len);
- if (ret)
+ if (ret) {
ip_vs_nfct_expect_related(skb, ct, n_cp,
IPPROTO_TCP, 0, 0);
+ if (skb->ip_summed == CHECKSUM_COMPLETE)
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ /* csum is updated */
+ ret = 1;
+ }
}
/*
diff -urp nf-next-2.6-a91fd26/linux/net/netfilter/ipvs/ip_vs_proto_tcp.c
linux/net/netfilter/ipvs/ip_vs_proto_tcp.c
--- nf-next-2.6-a91fd26/linux/net/netfilter/ipvs/ip_vs_proto_tcp.c
2010-10-16 12:46:09.514355652 +0300
+++ linux/net/netfilter/ipvs/ip_vs_proto_tcp.c 2010-10-16 12:46:47.935355696
+0300
@@ -120,6 +120,7 @@ tcp_snat_handler(struct sk_buff *skb,
struct tcphdr *tcph;
unsigned int tcphoff;
int oldlen;
+ int payload_csum = 0;
#ifdef CONFIG_IP_VS_IPV6
if (cp->af == AF_INET6)
@@ -134,13 +135,20 @@ tcp_snat_handler(struct sk_buff *skb,
return 0;
if (unlikely(cp->app != NULL)) {
+ int ret;
+
/* Some checks before mangling */
if (pp->csum_check && !pp->csum_check(cp->af, skb, pp))
return 0;
/* Call application helper if needed */
- if (!ip_vs_app_pkt_out(cp, skb))
+ if (!(ret = ip_vs_app_pkt_out(cp, skb)))
return 0;
+ /* ret=2: csum update is needed after payload mangling */
+ if (ret == 1)
+ oldlen = skb->len - tcphoff;
+ else
+ payload_csum = 1;
}
tcph = (void *)skb_network_header(skb) + tcphoff;
@@ -151,12 +159,13 @@ tcp_snat_handler(struct sk_buff *skb,
tcp_partial_csum_update(cp->af, tcph, &cp->daddr, &cp->vaddr,
htons(oldlen),
htons(skb->len - tcphoff));
- } else if (!cp->app) {
+ } else if (!payload_csum) {
/* Only port and addr are changed, do fast csum update */
tcp_fast_csum_update(cp->af, tcph, &cp->daddr, &cp->vaddr,
cp->dport, cp->vport);
if (skb->ip_summed == CHECKSUM_COMPLETE)
- skb->ip_summed = CHECKSUM_NONE;
+ skb->ip_summed = (cp->app && pp->csum_check) ?
+ CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
} else {
/* full checksum calculation */
tcph->check = 0;
@@ -174,6 +183,7 @@ tcp_snat_handler(struct sk_buff *skb,
skb->len - tcphoff,
cp->protocol,
skb->csum);
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
pp->name, tcph->check,
@@ -190,6 +200,7 @@ tcp_dnat_handler(struct sk_buff *skb,
struct tcphdr *tcph;
unsigned int tcphoff;
int oldlen;
+ int payload_csum = 0;
#ifdef CONFIG_IP_VS_IPV6
if (cp->af == AF_INET6)
@@ -204,6 +215,8 @@ tcp_dnat_handler(struct sk_buff *skb,
return 0;
if (unlikely(cp->app != NULL)) {
+ int ret;
+
/* Some checks before mangling */
if (pp->csum_check && !pp->csum_check(cp->af, skb, pp))
return 0;
@@ -212,8 +225,13 @@ tcp_dnat_handler(struct sk_buff *skb,
* Attempt ip_vs_app call.
* It will fix ip_vs_conn and iph ack_seq stuff
*/
- if (!ip_vs_app_pkt_in(cp, skb))
+ if (!(ret = ip_vs_app_pkt_in(cp, skb)))
return 0;
+ /* ret=2: csum update is needed after payload mangling */
+ if (ret == 1)
+ oldlen = skb->len - tcphoff;
+ else
+ payload_csum = 1;
}
tcph = (void *)skb_network_header(skb) + tcphoff;
@@ -226,12 +244,13 @@ tcp_dnat_handler(struct sk_buff *skb,
tcp_partial_csum_update(cp->af, tcph, &cp->vaddr, &cp->daddr,
htons(oldlen),
htons(skb->len - tcphoff));
- } else if (!cp->app) {
+ } else if (!payload_csum) {
/* Only port and addr are changed, do fast csum update */
tcp_fast_csum_update(cp->af, tcph, &cp->vaddr, &cp->daddr,
cp->vport, cp->dport);
if (skb->ip_summed == CHECKSUM_COMPLETE)
- skb->ip_summed = CHECKSUM_NONE;
+ skb->ip_summed = (cp->app && pp->csum_check) ?
+ CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
} else {
/* full checksum calculation */
tcph->check = 0;
diff -urp nf-next-2.6-a91fd26/linux/net/netfilter/ipvs/ip_vs_proto_udp.c
linux/net/netfilter/ipvs/ip_vs_proto_udp.c
--- nf-next-2.6-a91fd26/linux/net/netfilter/ipvs/ip_vs_proto_udp.c
2010-10-16 12:46:09.515355469 +0300
+++ linux/net/netfilter/ipvs/ip_vs_proto_udp.c 2010-10-16 12:46:47.936355945
+0300
@@ -121,6 +121,7 @@ udp_snat_handler(struct sk_buff *skb,
struct udphdr *udph;
unsigned int udphoff;
int oldlen;
+ int payload_csum = 0;
#ifdef CONFIG_IP_VS_IPV6
if (cp->af == AF_INET6)
@@ -135,6 +136,8 @@ udp_snat_handler(struct sk_buff *skb,
return 0;
if (unlikely(cp->app != NULL)) {
+ int ret;
+
/* Some checks before mangling */
if (pp->csum_check && !pp->csum_check(cp->af, skb, pp))
return 0;
@@ -142,8 +145,13 @@ udp_snat_handler(struct sk_buff *skb,
/*
* Call application helper if needed
*/
- if (!ip_vs_app_pkt_out(cp, skb))
+ if (!(ret = ip_vs_app_pkt_out(cp, skb)))
return 0;
+ /* ret=2: csum update is needed after payload mangling */
+ if (ret == 1)
+ oldlen = skb->len - udphoff;
+ else
+ payload_csum = 1;
}
udph = (void *)skb_network_header(skb) + udphoff;
@@ -156,12 +164,13 @@ udp_snat_handler(struct sk_buff *skb,
udp_partial_csum_update(cp->af, udph, &cp->daddr, &cp->vaddr,
htons(oldlen),
htons(skb->len - udphoff));
- } else if (!cp->app && (udph->check != 0)) {
+ } else if (!payload_csum && (udph->check != 0)) {
/* Only port and addr are changed, do fast csum update */
udp_fast_csum_update(cp->af, udph, &cp->daddr, &cp->vaddr,
cp->dport, cp->vport);
if (skb->ip_summed == CHECKSUM_COMPLETE)
- skb->ip_summed = CHECKSUM_NONE;
+ skb->ip_summed = (cp->app && pp->csum_check) ?
+ CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
} else {
/* full checksum calculation */
udph->check = 0;
@@ -181,6 +190,7 @@ udp_snat_handler(struct sk_buff *skb,
skb->csum);
if (udph->check == 0)
udph->check = CSUM_MANGLED_0;
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
pp->name, udph->check,
(char*)&(udph->check) - (char*)udph);
@@ -196,6 +206,7 @@ udp_dnat_handler(struct sk_buff *skb,
struct udphdr *udph;
unsigned int udphoff;
int oldlen;
+ int payload_csum = 0;
#ifdef CONFIG_IP_VS_IPV6
if (cp->af == AF_INET6)
@@ -210,6 +221,8 @@ udp_dnat_handler(struct sk_buff *skb,
return 0;
if (unlikely(cp->app != NULL)) {
+ int ret;
+
/* Some checks before mangling */
if (pp->csum_check && !pp->csum_check(cp->af, skb, pp))
return 0;
@@ -218,8 +231,13 @@ udp_dnat_handler(struct sk_buff *skb,
* Attempt ip_vs_app call.
* It will fix ip_vs_conn
*/
- if (!ip_vs_app_pkt_in(cp, skb))
+ if (!(ret = ip_vs_app_pkt_in(cp, skb)))
return 0;
+ /* ret=2: csum update is needed after payload mangling */
+ if (ret == 1)
+ oldlen = skb->len - udphoff;
+ else
+ payload_csum = 1;
}
udph = (void *)skb_network_header(skb) + udphoff;
@@ -232,12 +250,13 @@ udp_dnat_handler(struct sk_buff *skb,
udp_partial_csum_update(cp->af, udph, &cp->vaddr, &cp->daddr,
htons(oldlen),
htons(skb->len - udphoff));
- } else if (!cp->app && (udph->check != 0)) {
+ } else if (!payload_csum && (udph->check != 0)) {
/* Only port and addr are changed, do fast csum update */
udp_fast_csum_update(cp->af, udph, &cp->vaddr, &cp->daddr,
cp->vport, cp->dport);
if (skb->ip_summed == CHECKSUM_COMPLETE)
- skb->ip_summed = CHECKSUM_NONE;
+ skb->ip_summed = (cp->app && pp->csum_check) ?
+ CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
} else {
/* full checksum calculation */
udph->check = 0;
--
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