netfilter: nf_nat: add nf_nat_csum()
Add a static function nf_nat_csum() to replace the duplicate code in nf_nat_mangle_udp_packet() and __nf_nat_mangle_tcp_packet(). Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Patrick McHardy <kaber@trash.net>hifive-unleashed-5.1
parent
068e8a3032
commit
0abee5260b
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@ -153,6 +153,35 @@ void nf_nat_set_seq_adjust(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
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}
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}
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EXPORT_SYMBOL_GPL(nf_nat_set_seq_adjust);
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EXPORT_SYMBOL_GPL(nf_nat_set_seq_adjust);
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static void nf_nat_csum(struct sk_buff *skb, struct iphdr *iph, void *data,
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int datalen, __sum16 *check, int oldlen)
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{
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struct rtable *rt = skb_rtable(skb);
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if (skb->ip_summed != CHECKSUM_PARTIAL) {
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if (!(rt->rt_flags & RTCF_LOCAL) &&
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skb->dev->features & NETIF_F_V4_CSUM) {
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skb->ip_summed = CHECKSUM_PARTIAL;
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skb->csum_start = skb_headroom(skb) +
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skb_network_offset(skb) +
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iph->ihl * 4;
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skb->csum_offset = (void *)check - data;
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*check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
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datalen, iph->protocol, 0);
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} else {
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*check = 0;
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*check = csum_tcpudp_magic(iph->saddr, iph->daddr,
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datalen, iph->protocol,
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csum_partial(data, datalen,
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0));
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if (iph->protocol == IPPROTO_UDP && !*check)
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*check = CSUM_MANGLED_0;
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}
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} else
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inet_proto_csum_replace2(check, skb,
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htons(oldlen), htons(datalen), 1);
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}
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/* Generic function for mangling variable-length address changes inside
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/* Generic function for mangling variable-length address changes inside
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* NATed TCP connections (like the PORT XXX,XXX,XXX,XXX,XXX,XXX
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* NATed TCP connections (like the PORT XXX,XXX,XXX,XXX,XXX,XXX
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* command in FTP).
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* command in FTP).
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@ -169,7 +198,6 @@ int __nf_nat_mangle_tcp_packet(struct sk_buff *skb,
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const char *rep_buffer,
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const char *rep_buffer,
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unsigned int rep_len, bool adjust)
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unsigned int rep_len, bool adjust)
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{
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{
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struct rtable *rt = skb_rtable(skb);
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struct iphdr *iph;
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struct iphdr *iph;
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struct tcphdr *tcph;
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struct tcphdr *tcph;
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int oldlen, datalen;
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int oldlen, datalen;
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@ -192,26 +220,7 @@ int __nf_nat_mangle_tcp_packet(struct sk_buff *skb,
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match_offset, match_len, rep_buffer, rep_len);
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match_offset, match_len, rep_buffer, rep_len);
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datalen = skb->len - iph->ihl*4;
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datalen = skb->len - iph->ihl*4;
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if (skb->ip_summed != CHECKSUM_PARTIAL) {
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nf_nat_csum(skb, iph, tcph, datalen, &tcph->check, oldlen);
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if (!(rt->rt_flags & RTCF_LOCAL) &&
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skb->dev->features & NETIF_F_V4_CSUM) {
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skb->ip_summed = CHECKSUM_PARTIAL;
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skb->csum_start = skb_headroom(skb) +
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skb_network_offset(skb) +
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iph->ihl * 4;
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skb->csum_offset = offsetof(struct tcphdr, check);
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tcph->check = ~tcp_v4_check(datalen,
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iph->saddr, iph->daddr, 0);
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} else {
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tcph->check = 0;
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tcph->check = tcp_v4_check(datalen,
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iph->saddr, iph->daddr,
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csum_partial(tcph,
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datalen, 0));
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}
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} else
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inet_proto_csum_replace2(&tcph->check, skb,
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htons(oldlen), htons(datalen), 1);
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if (adjust && rep_len != match_len)
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if (adjust && rep_len != match_len)
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nf_nat_set_seq_adjust(ct, ctinfo, tcph->seq,
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nf_nat_set_seq_adjust(ct, ctinfo, tcph->seq,
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@ -240,7 +249,6 @@ nf_nat_mangle_udp_packet(struct sk_buff *skb,
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const char *rep_buffer,
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const char *rep_buffer,
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unsigned int rep_len)
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unsigned int rep_len)
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{
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{
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struct rtable *rt = skb_rtable(skb);
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struct iphdr *iph;
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struct iphdr *iph;
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struct udphdr *udph;
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struct udphdr *udph;
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int datalen, oldlen;
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int datalen, oldlen;
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@ -274,29 +282,7 @@ nf_nat_mangle_udp_packet(struct sk_buff *skb,
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if (!udph->check && skb->ip_summed != CHECKSUM_PARTIAL)
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if (!udph->check && skb->ip_summed != CHECKSUM_PARTIAL)
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return 1;
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return 1;
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if (skb->ip_summed != CHECKSUM_PARTIAL) {
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nf_nat_csum(skb, iph, udph, datalen, &udph->check, oldlen);
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if (!(rt->rt_flags & RTCF_LOCAL) &&
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skb->dev->features & NETIF_F_V4_CSUM) {
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skb->ip_summed = CHECKSUM_PARTIAL;
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skb->csum_start = skb_headroom(skb) +
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skb_network_offset(skb) +
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iph->ihl * 4;
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skb->csum_offset = offsetof(struct udphdr, check);
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udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
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datalen, IPPROTO_UDP,
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0);
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} else {
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udph->check = 0;
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udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
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datalen, IPPROTO_UDP,
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csum_partial(udph,
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datalen, 0));
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if (!udph->check)
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udph->check = CSUM_MANGLED_0;
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}
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} else
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inet_proto_csum_replace2(&udph->check, skb,
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htons(oldlen), htons(datalen), 1);
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return 1;
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return 1;
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}
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}
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