presharedServerudp.c (2789B)
1 #! /usr/bin/env sheepy 2 3 #include "libsheepyObject.h" 4 5 #include <sys/socket.h> 6 #include <netinet/in.h> 7 8 #include "sel.h" 9 10 int main(int ac, char **av){ 11 12 setLogMode(LOG_FUNC); 13 14 if (not selInit()) ret 1; 15 16 // load keys 17 const char* clientSecretFilename = "presharedClientSecret.bin"; 18 const char* clientPublicFilename = "presharedClientPublic.bin"; 19 const char* serverSecretFilename = "presharedServerSecret.bin"; 20 const char* serverPublicFilename = "presharedServerPublic.bin"; 21 keyst clientKeys = init0Var; 22 keyst serverKeys = init0Var; 23 24 if (isPath(serverPublicFilename) and isPath(serverSecretFilename) and isPath(clientPublicFilename)) { 25 logI("Loading server keys"); 26 pError0(bLReadFile(serverSecretFilename, serverKeys.secretKey, sizeof(serverKeys.secretKey))); 27 pError0(bLReadFile(serverPublicFilename, serverKeys.publicKey, sizeof(serverKeys.publicKey))); 28 pError0(bLReadFile(clientPublicFilename, serverKeys.remotePublicKey, sizeof(serverKeys.remotePublicKey))); 29 } 30 else { 31 logE("Failed to load the server keys. Stop. Run ./presharedClient.c generate keys"); 32 ret 1; 33 } 34 35 36 // start event loop 37 int sock; 38 struct sockaddr_in server; 39 typ struct PACKED { 40 u64 time; 41 char buf[64*1024]; 42 } payloadt; 43 typ struct PACKED { 44 u8 nonce[crypto_box_NONCEBYTES]; 45 i32 len; 46 payloadt payload; 47 } packett; 48 packett data = init0Var; 49 int rval; 50 51 sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); 52 if (sock < 0){ 53 perror("Failed to create socket"); 54 ret 1; 55 } 56 57 server.sin_family = AF_INET; 58 server.sin_addr.s_addr = INADDR_ANY; 59 server.sin_port = htons(5000); 60 61 if (bind(sock, (struct sockaddr *) &server, sizeof(server))){ 62 perror("bind failed"); 63 ret 1; 64 } 65 66 listen(sock, SOMAXCONN); 67 68 struct sockaddr_in addr; 69 70 forever { 71 socklen_t ln = sizeof(addr); 72 ssize_t r = recvfrom(sock, &data, sizeof(data), 0, (struct sockaddr *) &addr, &ln); 73 if (r == -1) 74 perror("recvfrom failed"); 75 elif (r != data.len + sizeof(data.len) + sizeof(data.nonce)) { 76 logE("Wrong size"); 77 continue; 78 } 79 80 memcpy(serverKeys.nonce, data.nonce, sizeof(serverKeys.nonce)); 81 82 payloadt decrypted; 83 int len = selPublicDecrypt((u8*)&decrypted, sizeof(decrypted), (u8*)&data.payload, data.len, &serverKeys); 84 85 if (!len) { 86 logE("failed to decrypt"); 87 continue; 88 } 89 90 u64 now = getCurrentUnixTime(); 91 if (decrypted.time < now - 1 or decrypted.time > now + 1) { 92 logW("Dropping packet. Wrong timestamp %"PRIu64" now %"PRIu64" diff %"PRIi64, decrypted.time, now, (i64)now - (i64)decrypted.time); 93 continue; 94 } 95 96 decrypted.buf[len - sizeof(decrypted.time)] = 0; 97 98 logI("decrypted: %s", decrypted.buf); 99 } 100 } 101 // vim: set expandtab ts=2 sw=2: