mirror of
https://code.semirocket.science/wrapsix
synced 2024-11-10 00:01:01 +02:00
Fixed IPv4 checksum computation
Added missing checksum recheck in UDP
This commit is contained in:
parent
d6f93792cd
commit
495d68296a
@ -95,11 +95,11 @@ unsigned short checksum_ipv4(struct s_ipv4_addr ip_src,
|
|||||||
header->ip_dest = ip_dest;
|
header->ip_dest = ip_dest;
|
||||||
header->zeros = 0x0;
|
header->zeros = 0x0;
|
||||||
header->proto = proto;
|
header->proto = proto;
|
||||||
header->len = htonl((unsigned int) length);
|
header->len = htons(length);
|
||||||
|
|
||||||
memcpy(buffer + sizeof(struct s_ipv4_pseudo), payload, (int) length);
|
memcpy(buffer + sizeof(struct s_ipv4_pseudo), payload, (int) length);
|
||||||
|
|
||||||
sum = checksum(buffer, sizeof(struct s_ipv6_pseudo) + (int) length);
|
sum = checksum(buffer, sizeof(struct s_ipv4_pseudo) + (int) length);
|
||||||
|
|
||||||
free(buffer);
|
free(buffer);
|
||||||
|
|
||||||
|
@ -53,7 +53,7 @@ struct s_ipv4_pseudo {
|
|||||||
struct s_ipv4_addr ip_dest; /* 32 b; destination address */
|
struct s_ipv4_addr ip_dest; /* 32 b; destination address */
|
||||||
unsigned char zeros; /* 8 b */
|
unsigned char zeros; /* 8 b */
|
||||||
unsigned char proto; /* 8 b; protocol in payload */
|
unsigned char proto; /* 8 b; protocol in payload */
|
||||||
unsigned int len; /* 32 b; payload length */
|
unsigned short len; /* 16 b; payload length */
|
||||||
} __attribute__ ((__packed__));
|
} __attribute__ ((__packed__));
|
||||||
|
|
||||||
int ipv4(struct s_ethernet *eth, char *packet);
|
int ipv4(struct s_ethernet *eth, char *packet);
|
||||||
|
26
src/udp.c
26
src/udp.c
@ -58,7 +58,20 @@ int udp_ipv4(struct s_ethernet *eth, struct s_ipv4 *ip4, char *payload,
|
|||||||
/* parse UDP header */
|
/* parse UDP header */
|
||||||
udp = (struct s_udp *) payload;
|
udp = (struct s_udp *) payload;
|
||||||
|
|
||||||
/* TODO: checksum recheck */
|
/* checksum recheck */
|
||||||
|
if (udp->checksum != 0x0000) {
|
||||||
|
orig_checksum = udp->checksum;
|
||||||
|
udp->checksum = 0;
|
||||||
|
udp->checksum = checksum_ipv4(ip4->ip_src, ip4->ip_dest,
|
||||||
|
payload_size, IPPROTO_UDP,
|
||||||
|
(unsigned char *) udp);
|
||||||
|
|
||||||
|
if (udp->checksum != orig_checksum) {
|
||||||
|
/* packet is corrupted and shouldn't be processed */
|
||||||
|
printf("[Debug] Wrong checksum\n");
|
||||||
|
return 1;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
/* find connection in NAT */
|
/* find connection in NAT */
|
||||||
connection = nat_in(nat4_udp, ip4->ip_src, udp->port_src, udp->port_dest);
|
connection = nat_in(nat4_udp, ip4->ip_src, udp->port_src, udp->port_dest);
|
||||||
@ -185,16 +198,17 @@ int udp_ipv6(struct s_ethernet *eth, struct s_ipv6 *ip6, char *payload)
|
|||||||
udp->port_src = connection->ipv4_port_src;
|
udp->port_src = connection->ipv4_port_src;
|
||||||
|
|
||||||
/* compute UDP checksum */
|
/* compute UDP checksum */
|
||||||
udp->checksum = 0;
|
udp->checksum = 0x0;
|
||||||
/* TODO: checksum computation; in IPv4 it's optional in UDP */
|
udp->checksum = checksum_ipv4(ip4->ip_src, ip4->ip_dest,
|
||||||
|
htons(ip6->len), IPPROTO_UDP,
|
||||||
|
(unsigned char *) payload);
|
||||||
|
|
||||||
/* copy the payload data (with new checksum) */
|
/* copy the payload data (with new checksum) */
|
||||||
memcpy(packet + sizeof(struct s_ipv4), payload, htons(ip6->len));
|
memcpy(packet + sizeof(struct s_ipv4), payload, htons(ip6->len));
|
||||||
|
|
||||||
/* compute IPv4 checksum */
|
/* compute IPv4 checksum */
|
||||||
ip4->checksum = checksum_ipv4(ip4->ip_src, ip4->ip_dest,
|
ip4->checksum = 0x0;
|
||||||
htons(ip4->len), IPPROTO_UDP,
|
ip4->checksum = checksum(ip4, sizeof(struct s_ipv4));
|
||||||
(unsigned char *) udp);
|
|
||||||
|
|
||||||
/* send translated packet */
|
/* send translated packet */
|
||||||
printf("[Debug] transmitting\n");
|
printf("[Debug] transmitting\n");
|
||||||
|
Loading…
Reference in New Issue
Block a user