Move `check_network` to separate files.

4 files changed, 110 insertions, 88 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 67e49f9..efdf954 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,4 +4,4 @@ project(netmon C)
 set(CMAKE_C_STANDARD 99)
 add_compile_definitions(DEBUG)
 
-add_executable(netmon netmon.c logging.c logging.h)
+add_executable(netmon netmon.c logging.c logging.h netcheck.c netcheck.h)
diff --git a/netcheck.c b/netcheck.c
new file mode 100644
index 0000000..4900e0f
--- /dev/null
+++ b/netcheck.c
@@ -0,0 +1,96 @@
+//
+// Created by Keuin on 2021/12/29.
+//
+
+#include <netdb.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "logging.h"
+#include "netcheck.h"
+
+/**
+ * Check network availability.
+ * @return Zero if success, non-zero if failed.
+ */
+int check_network(void *logger) {
+#define RETURN(r) do { rv = (r); goto RET; } while(0)
+#define READ_SIZE 32
+
+    int sock = -1, rv = 0;
+    struct sockaddr_in serv_addr;
+    const char *msg = "GET / HTTP/1.1\r\n"
+                      "Host: www.gov.cn\r\n"
+                      "\r\n";
+
+    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
+        perror("socket()");
+        log_error(logger, "socket() failed.");
+        RETURN(-1);
+    }
+
+    const struct hostent *host = gethostbyname("www.gov.cn"); // TODO cache this
+
+    if (!host) {
+        herror("gethostbyname()");
+        log_error(logger, "Cannot resolve test host.");
+        RETURN(-1);
+    }
+
+    if (host->h_length <= 0) {
+        log_error(logger, "Test host does not have at least one address.");
+        RETURN(-1);
+    }
+
+    serv_addr.sin_family = AF_INET;
+    serv_addr.sin_port = htons(80);
+    serv_addr.sin_addr = **((struct in_addr **) host->h_addr_list);
+
+    if (connect(sock, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
+        log_error(logger, "connect() failed.");
+        RETURN(-1);
+    }
+
+    ssize_t ss = 0; // send size
+    while (ss < strlen(msg)) {
+        ssize_t rd = send(sock, msg, strlen(msg), 0);
+        if (rd < 0) {
+            perror("send()");
+            log_error(logger, "send() failed.");
+            RETURN(-1);
+        }
+        ss += rd;
+    }
+
+    log_debug(logger, "HTTP request is sent. Reading response.");
+    char response[READ_SIZE] = {0};
+    ssize_t rs = 0; // receive size
+    while (rs < READ_SIZE) {
+        ssize_t rd = read(sock, response, READ_SIZE - rs);
+        if (rd < 0) {
+            perror("read()");
+            log_error(logger, "read() failed.");
+            RETURN(-1);
+        } else {
+            rs += rd;
+        }
+    }
+
+    const char *expected = "HTTP/1.1 200 OK\r\n";
+    if (memcmp(response, expected, strlen(expected)) != 0) {
+        char buf[64];
+        snprintf(buf, 63, "Unexpected response: %s", response);
+        log_error(logger, buf);
+        RETURN(-1);
+    }
+    RETURN(0);
+
+    RET:
+    if (sock >= 0) close(sock);
+    return rv;
+#undef RETURN
+#undef READ_SIZE
+}
\ No newline at end of file
diff --git a/netcheck.h b/netcheck.h
new file mode 100644
index 0000000..3bea521
--- /dev/null
+++ b/netcheck.h
@@ -0,0 +1,11 @@
+//
+// Created by Keuin on 2021/12/29.
+//
+
+#ifndef NETMON_NETCHECK_H
+#define NETMON_NETCHECK_H
+
+
+int check_network(void *logger);
+
+#endif //NETMON_NETCHECK_H
diff --git a/netmon.c b/netmon.c
index 2c500d9..0b0a434 100644
--- a/netmon.c
+++ b/netmon.c
@@ -1,13 +1,11 @@
 #include "logging.h"
+#include "netcheck.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
 #include <sys/stat.h>
 
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <netdb.h>
 
 const char *logfile = "netmon.log";
 int check_interval_seconds = 30; // seconds to sleep between checks
@@ -88,89 +86,6 @@ void daemonize() {
 //    }
 //}
 
-/**
- * Check network availability.
- * @return Zero if success, non-zero if failed.
- */
-int check_network() {
-#define RETURN(r) do { rv = (r); goto RET; } while(0)
-#define READ_SIZE 32
-
-    int sock = -1, rv = 0;
-    struct sockaddr_in serv_addr;
-    const char *msg = "GET / HTTP/1.1\r\n"
-                      "Host: www.gov.cn\r\n"
-                      "\r\n";
-
-    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
-        perror("socket()");
-        log_error(logger, "socket() failed.");
-        RETURN(-1);
-    }
-
-    const struct hostent *host = gethostbyname("www.gov.cn"); // TODO cache this
-
-    if (!host) {
-        herror("gethostbyname()");
-        log_error(logger, "Cannot resolve test host.");
-        RETURN(-1);
-    }
-
-    if (host->h_length <= 0) {
-        log_error(logger, "Test host does not have at least one address.");
-        RETURN(-1);
-    }
-
-    serv_addr.sin_family = AF_INET;
-    serv_addr.sin_port = htons(80);
-    serv_addr.sin_addr = **((struct in_addr **) host->h_addr_list);
-
-    if (connect(sock, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
-        log_error(logger, "connect() failed.");
-        RETURN(-1);
-    }
-
-    ssize_t ss = 0; // send size
-    while (ss < strlen(msg)) {
-        ssize_t rd = send(sock, msg, strlen(msg), 0);
-        if (rd < 0) {
-            perror("send()");
-            log_error(logger, "send() failed.");
-            RETURN(-1);
-        }
-        ss += rd;
-    }
-
-    log_debug(logger, "HTTP request is sent. Reading response.");
-    char response[READ_SIZE] = {0};
-    ssize_t rs = 0; // receive size
-    while (rs < READ_SIZE) {
-        ssize_t rd = read(sock, response, READ_SIZE - rs);
-        if (rd < 0) {
-            perror("read()");
-            log_error(logger, "read() failed.");
-            RETURN(-1);
-        } else {
-            rs += rd;
-        }
-    }
-
-    const char *expected = "HTTP/1.1 200 OK\r\n";
-    if (memcmp(response, expected, strlen(expected)) != 0) {
-        char buf[64];
-        snprintf(buf, 63, "Unexpected response: %s", response);
-        log_error(logger, buf);
-        RETURN(-1);
-    }
-    RETURN(0);
-
-    RET:
-    if (sock >= 0) close(sock);
-    return rv;
-#undef RETURN
-#undef READ_SIZE
-}
-
 void loop() {
     // check network and sleep
     // if fails too many times continuously, set require_reboot flag and return
@@ -179,7 +94,7 @@ void loop() {
 #pragma ide diagnostic ignored "EndlessLoop"
     while (1) {
         log_info(logger, "Check network.");
-        if (check_network() != 0) {
+        if (check_network(logger) != 0) {
             ++failures;
             char buf[64];
             snprintf(buf, 63, "Network failure detected. counter=%d", failures);