Make sender use getaddrinfo to lookup loggin host name

1 files changed, 30 insertions, 18 deletions

diff --git a/sender.c b/sender.c
index 19a3bed..c56cb8c 100644
--- a/sender.c
+++ b/sender.c
@@ -5,13 +5,13 @@
 #include <inttypes.h>
 #include <arpa/inet.h>
 #include <unistd.h>
+#include <netdb.h>
 
 #include <mbedtls/pk.h>
 #include <mbedtls/entropy.h>
 #include "mbedtls/ctr_drbg.h"
 #include "mbedtls/gcm.h"
 
-const unsigned short PORT = 58132;
 
 static const unsigned char pubkey[] =
 "-----BEGIN PUBLIC KEY-----\n"
@@ -25,10 +25,17 @@ static const unsigned char pubkey[] =
 "-----END PUBLIC KEY----- \n";
 
 static const unsigned char pp[] = "IJUHZGFDXTZKHJKHGFDHZLUÖDRTFGHHJGHH";
+static const char *logging_host = "localhost";
+static const char *logging_port = "58132";
+
+static struct sockaddr_storage logging_host_address;
+static socklen_t logging_host_address_len = 0;
+static int logging_socket = -1;
 
 enum { SESSION_ID_LENGTH = 8, AES_KEY_LENGTH = 16, GCM_IV_LENGTH = 16, GCM_TAG_LENGTH = 16 };
 static uint64_t session_id = 0x0123456789abcdef;
 static uint8_t aes_key[16] = { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef };
+static mbedtls_gcm_context ctx;
 
 void send_udp(int sock, mbedtls_ctr_drbg_context *ctr_drbg, const uint8_t *text, size_t len) {
     uint8_t iv[GCM_IV_LENGTH];
@@ -40,20 +47,11 @@ void send_udp(int sock, mbedtls_ctr_drbg_context *ctr_drbg, const uint8_t *text,
     memcpy(output + 1, (uint8_t*)&session_id, SESSION_ID_LENGTH);
     memcpy(output + 1 + SESSION_ID_LENGTH, iv, GCM_IV_LENGTH);
 
-    mbedtls_gcm_context ctx;
-    mbedtls_gcm_init(&ctx);
-    mbedtls_gcm_setkey(&ctx, MBEDTLS_CIPHER_ID_AES, aes_key, 8 * AES_KEY_LENGTH);
 
     if (!mbedtls_gcm_crypt_and_tag(&ctx, MBEDTLS_GCM_ENCRYPT, len, iv, GCM_IV_LENGTH, (uint8_t*)&session_id, SESSION_ID_LENGTH,
                                   text, output + 1 + SESSION_ID_LENGTH + GCM_IV_LENGTH + GCM_TAG_LENGTH, GCM_TAG_LENGTH,
                                   output + 1 + SESSION_ID_LENGTH + GCM_IV_LENGTH)) {
-        struct sockaddr_in to;
-        memset(&to, 0, sizeof(to));
-        to.sin_family      = AF_INET;
-        to.sin_addr.s_addr = inet_addr("127.0.0.1");
-        to.sin_port        = htons(PORT);
-
-        sendto(sock, output, total_length, 0, (struct sockaddr*)&to, sizeof(to));
+        sendto(sock, output, total_length, 0, (struct sockaddr*)&logging_host_address, logging_host_address_len);
     }
 
     mbedtls_gcm_free(&ctx);
@@ -80,13 +78,10 @@ void new_session(int sock, mbedtls_ctr_drbg_context *ctr_drbg) {
 
     mbedtls_pk_free(&pk);
 
-    struct sockaddr_in to;
-    memset(&to, 0, sizeof(to));
-    to.sin_family      = AF_INET;
-    to.sin_addr.s_addr = inet_addr("127.0.0.1");
-    to.sin_port        = htons(PORT);
+    sendto(sock, output, olen + 1 + SESSION_ID_LENGTH, 0, (struct sockaddr*)&logging_host_address, logging_host_address_len);
 
-    sendto(sock, output, olen + 1 + SESSION_ID_LENGTH, 0, (struct sockaddr*)&to, sizeof(to));
+    mbedtls_gcm_init(&ctx);
+    mbedtls_gcm_setkey(&ctx, MBEDTLS_CIPHER_ID_AES, aes_key, 8 * AES_KEY_LENGTH);
 }
 
 int main() {
@@ -97,7 +92,24 @@ int main() {
     mbedtls_ctr_drbg_init(&ctr_drbg);
     mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy, pp, sizeof(pp));
 
-    int sock = socket(AF_INET, SOCK_DGRAM, 0);
+    struct addrinfo hints, *result, *rp;
+    memset (&hints, 0, sizeof (hints));
+    hints.ai_socktype = SOCK_DGRAM;
+
+    int sock = -1, res = getaddrinfo(logging_host, logging_port, &hints, &result);
+    if (res != 0)
+        errx(EXIT_FAILURE, "getaddrinfo: %s\n", gai_strerror(res));
+
+    for (rp = result; rp != NULL; rp = rp->ai_next) {
+        sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+        if (sock == -1)
+            continue;
+        memcpy(&logging_host_address, rp->ai_addr, rp->ai_addrlen);
+        logging_host_address_len = rp->ai_addrlen;
+    }
+    if (sock == -1)
+        errx(EXIT_FAILURE, "Can't open socket");
+    freeaddrinfo(result);
 
     new_session(sock, &ctr_drbg);