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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: