+ sum0 = icmp0->checksum;
+ sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
+ identifier);
+ icmp0->checksum = ip_csum_fold (sum0);
+ }
+ else
+ {
+ if (!ip4_header_checksum_is_valid (inner_ip0))
+ {
+ next0 = SNAT_IN2OUT_NEXT_DROP;
+ goto out;
+ }
+
+ old_addr0 = inner_ip0->dst_address.as_u32;
+ inner_ip0->dst_address = s0->out2in.addr;
+ new_addr0 = inner_ip0->src_address.as_u32;
+
+ sum0 = icmp0->checksum;
+ sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+ dst_address /* changed member */);
+ icmp0->checksum = ip_csum_fold (sum0);
+
+ switch (key0.protocol)
+ {
+ case SNAT_PROTOCOL_ICMP:
+ old_id0 = inner_echo0->identifier;
+ new_id0 = s0->out2in.port;
+ inner_echo0->identifier = new_id0;
+
+ sum0 = icmp0->checksum;
+ sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
+ identifier);
+ icmp0->checksum = ip_csum_fold (sum0);
+ break;
+ case SNAT_PROTOCOL_UDP:
+ case SNAT_PROTOCOL_TCP:
+ old_id0 = ((tcp_udp_header_t*)l4_header)->dst_port;
+ new_id0 = s0->out2in.port;
+ ((tcp_udp_header_t*)l4_header)->dst_port = new_id0;
+
+ sum0 = icmp0->checksum;
+ sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
+ dst_port);
+ icmp0->checksum = ip_csum_fold (sum0);
+ break;
+ default:
+ ASSERT(0);
+ }
+ }