1 files changed, 83 insertions, 0 deletions
diff --git a/common.h b/common.h
new file mode 100644
index 0000000..2059d81
--- /dev/null
+++ b/common.h
@@ -0,0 +1,83 @@
+/* common (not config, need code patch after change) */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/select.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/ioctl.h>
+#include <termios.h>
+#include <time.h>
+
+#include "shorttypes.h"
+#include "crypto-sponge.h"
+
+#define ERRDIE(a, b) if ((a) == -1) perror((b)), exit(1)
+
+#define NONCE_SZ 16
+#define HMAC_SZ  16
+
+#define MIN_PKT_SZ NONCE_SZ + HMAC_SZ + 4 + 4 + 8 + 1
+#if MAX_PKT_SZ < MIN_PKT_SZ
+#error "MAX_PKT_SZ < MIN_PKT_SZ"
+#endif
+
+#define CONNECT (u16)32
+#define PING    (u16)4
+#define SSTATE  (u16)8
+
+u8  key[32];
+u8  password[PASSWORD_BUF_SZ];
+u32 prng_state[14];
+
+
+static void send_pkt
+(s32 skt, void *buf, u16 sz, struct sockaddr_storage *addr){
+	ssize_t res;
+	u8 *nonce, *tag;
+
+	/* nonce, tag */
+	nonce = (u8*)buf + sz;
+	tag = nonce + NONCE_SZ;
+	duplex257_prng_rand16(prng_state, nonce);
+
+	/* encrypt */
+	duplex257_ae_encrypt(key, nonce, tag, buf, sz);
+	sz += NONCE_SZ + HMAC_SZ;
+
+	/* send */
+	res = sendto(skt, buf, sz, 0,(struct sockaddr*)addr, sizeof(*addr));
+	ERRDIE(res, "sendto");
+	return;
+}
+
+static s32 recv_pkt
+(s32 skt, void *buf, u16 sz, struct sockaddr_storage *addr){
+	socklen_t skl;
+	s32 res;
+	u8 *nonce, *rtag;
+	u8 tag[HMAC_SZ];
+
+	/* recv */
+	skl = sizeof(*addr);
+	res = recvfrom(skt, buf, sz, 0, (struct sockaddr*)addr, &skl);
+	ERRDIE(res, "recvfrom");
+
+	/* drop packet if it too small */
+	if (res < 4 + NONCE_SZ + HMAC_SZ) return -1;
+
+	/* nonce, recieved tag */
+	rtag = buf + res - HMAC_SZ;
+	nonce  = rtag - NONCE_SZ;
+
+	/* decrypt */
+	res -= NONCE_SZ + HMAC_SZ;
+	duplex257_ae_decrypt(key, nonce, tag, buf, res);
+	if (0 != memcmp(tag, rtag, HMAC_SZ)) return -1;
+
+	return res;
+}
+