mirror of
https://github.com/lwip-tcpip/lwip.git
synced 2024-08-23 06:35:57 +00:00
28 lines
1.4 KiB
Plaintext
28 lines
1.4 KiB
Plaintext
|
This folder provides an example implementation of how to add custom tcp header
|
||
|
options and custom socket options.
|
||
|
|
||
|
It does this by implementing the (seldom used) tcp md5 signature.
|
||
|
|
||
|
To enable it, add an LWIP_HOOK_FILENAME hook file, include tcp_md5.h in it and
|
||
|
define these hooks:
|
||
|
|
||
|
#define LWIP_HOOK_TCP_INPACKET_PCB(pcb, hdr, optlen, opt1len, opt2, p) tcp_md5_check_inpacket(pcb, hdr, optlen, opt1len, opt2, p)
|
||
|
#define LWIP_HOOK_TCP_OPT_LENGTH_SEGMENT(pcb, internal_len) tcp_md5_get_additional_option_length(pcb, internal_len)
|
||
|
#define LWIP_HOOK_TCP_ADD_TX_OPTIONS(p, hdr, pcb, opts) tcp_md5_add_tx_options(p, hdr, pcb, opts)
|
||
|
#define LWIP_HOOK_SOCKETS_SETSOCKOPT(s, sock, level, optname, optval, optlen, err) tcp_md5_setsockopt_hook(sock, level, optname, optval, optlen, err)
|
||
|
|
||
|
Then, in your sockets application, enable md5 signature on a socket like this:
|
||
|
|
||
|
struct tcp_md5sig md5;
|
||
|
struct sockaddr_storage addr_remote; /* Initialize this to remote address and port */
|
||
|
memcpy(&md5.tcpm_addr, &addr_remote, sizeof(addr_remote));
|
||
|
strcpy(md5.tcpm_key, key); /* this is the md5 key per connection */
|
||
|
md5.tcpm_keylen = strlen(key);
|
||
|
if ((ret = setsockopt(sockfd, IPPROTO_TCP, TCP_MD5SIG, &md5, sizeof(md5))) < 0) {
|
||
|
perror("setsockopt TCP_MD5SIG");
|
||
|
return;
|
||
|
}
|
||
|
|
||
|
After that, your connection (client) or all incoming connections (server) require
|
||
|
tcp md5 signatures.
|