diff options
| author | Gao feng <gaofeng@cn.fujitsu.com> | 2013-09-26 07:00:30 (GMT) |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2013-09-27 14:17:59 (GMT) |
| commit | de1389b11686f436c81d696b5a33eec2bc975665 (patch) | |
| tree | 90bc6a006f109fe8258c3781d3f6b76e68377e1b | |
| parent | b21613aeb649293946556410ff10dbb8c639f298 (diff) | |
| download | linux-de1389b11686f436c81d696b5a33eec2bc975665.tar.xz | |
netfilter: xt_TCPMSS: Get mtu only if clamp-mss-to-pmtu is specified
This patch refactors the code to skip tcpmss_reverse_mtu if no
clamp-mss-to-pmtu is specified.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | net/netfilter/xt_TCPMSS.c | 70 |
1 files changed, 36 insertions, 34 deletions
diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c index cd24290..62776de 100644 --- a/net/netfilter/xt_TCPMSS.c +++ b/net/netfilter/xt_TCPMSS.c @@ -43,10 +43,41 @@ optlen(const u_int8_t *opt, unsigned int offset) return opt[offset+1]; } +static u_int32_t tcpmss_reverse_mtu(const struct sk_buff *skb, + unsigned int family) +{ + struct flowi fl; + const struct nf_afinfo *ai; + struct rtable *rt = NULL; + u_int32_t mtu = ~0U; + + if (family == PF_INET) { + struct flowi4 *fl4 = &fl.u.ip4; + memset(fl4, 0, sizeof(*fl4)); + fl4->daddr = ip_hdr(skb)->saddr; + } else { + struct flowi6 *fl6 = &fl.u.ip6; + + memset(fl6, 0, sizeof(*fl6)); + fl6->daddr = ipv6_hdr(skb)->saddr; + } + rcu_read_lock(); + ai = nf_get_afinfo(family); + if (ai != NULL) + ai->route(&init_net, (struct dst_entry **)&rt, &fl, false); + rcu_read_unlock(); + + if (rt != NULL) { + mtu = dst_mtu(&rt->dst); + dst_release(&rt->dst); + } + return mtu; +} + static int tcpmss_mangle_packet(struct sk_buff *skb, const struct xt_action_param *par, - unsigned int in_mtu, + unsigned int family, unsigned int tcphoff, unsigned int minlen) { @@ -76,6 +107,8 @@ tcpmss_mangle_packet(struct sk_buff *skb, return -1; if (info->mss == XT_TCPMSS_CLAMP_PMTU) { + unsigned int in_mtu = tcpmss_reverse_mtu(skb, family); + if (dst_mtu(skb_dst(skb)) <= minlen) { net_err_ratelimited("unknown or invalid path-MTU (%u)\n", dst_mtu(skb_dst(skb))); @@ -165,37 +198,6 @@ tcpmss_mangle_packet(struct sk_buff *skb, return TCPOLEN_MSS; } -static u_int32_t tcpmss_reverse_mtu(const struct sk_buff *skb, - unsigned int family) -{ - struct flowi fl; - const struct nf_afinfo *ai; - struct rtable *rt = NULL; - u_int32_t mtu = ~0U; - - if (family == PF_INET) { - struct flowi4 *fl4 = &fl.u.ip4; - memset(fl4, 0, sizeof(*fl4)); - fl4->daddr = ip_hdr(skb)->saddr; - } else { - struct flowi6 *fl6 = &fl.u.ip6; - - memset(fl6, 0, sizeof(*fl6)); - fl6->daddr = ipv6_hdr(skb)->saddr; - } - rcu_read_lock(); - ai = nf_get_afinfo(family); - if (ai != NULL) - ai->route(&init_net, (struct dst_entry **)&rt, &fl, false); - rcu_read_unlock(); - - if (rt != NULL) { - mtu = dst_mtu(&rt->dst); - dst_release(&rt->dst); - } - return mtu; -} - static unsigned int tcpmss_tg4(struct sk_buff *skb, const struct xt_action_param *par) { @@ -204,7 +206,7 @@ tcpmss_tg4(struct sk_buff *skb, const struct xt_action_param *par) int ret; ret = tcpmss_mangle_packet(skb, par, - tcpmss_reverse_mtu(skb, PF_INET), + PF_INET, iph->ihl * 4, sizeof(*iph) + sizeof(struct tcphdr)); if (ret < 0) @@ -233,7 +235,7 @@ tcpmss_tg6(struct sk_buff *skb, const struct xt_action_param *par) if (tcphoff < 0) return NF_DROP; ret = tcpmss_mangle_packet(skb, par, - tcpmss_reverse_mtu(skb, PF_INET6), + PF_INET6, tcphoff, sizeof(*ipv6h) + sizeof(struct tcphdr)); if (ret < 0) |