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