Implemented initial core/ping.

A fake plaintext ping/pong implementation, for now it's just
   to use as a POC for multistream and secio.

core/Makefile

@@ -2,7 +2,7 @@ CC = gcc
 CFLAGS = -O0 -I../include -I../../c-libp2p/include -I../../c-protobuf -Wall
 LFLAGS = 
 DEPS = builder.h ipfs_node.h
-OBJS = builder.o daemon.o null.o
+OBJS = builder.o daemon.o null.o ping.o
 
 %.o: %.c $(DEPS)
 	$(CC) -c -o $@ $< $(CFLAGS)

core/null.c

@@ -1,20 +1,39 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <string.h>
 #include <unistd.h>
 #include <pthread.h>
 #include "libp2p/net/p2pnet.h"
 #include "ipfs/core/daemon.h"
 
+#define BUF_SIZE 4096
+
 void *ipfs_null_connection (void *ptr)
 {
     struct null_connection_params *connection_param;
+    char b[BUF_SIZE];
+    int len;
 
     connection_param = (struct null_connection_params*) ptr;
 
     // TODO: multistream + secio + message.
     fprintf(stderr, "Connection %d, count %d\n", connection_param->socket, *(connection_param->count));
 
+    for(;;) {
+        len = socket_read(connection_param->socket, b, sizeof(b)-1, 0);
+        if (len > 0) {
+            while (b[len-1] == '\r' || b[len-1] == '\n') len--;
+            b[len] = '\0';
+            fprintf(stderr, "Recv: '%s'\n", b);
+            if (strcmp (b, "ping") == 0) {
+                socket_write(connection_param->socket, "pong", 4, 0);
+            }
+        } else if(len < 0) {
+            break;
+        }
+    }
+
     close (connection_param->socket); // close socket.
     (*(connection_param->count))--; // update counter.
     free (connection_param);

core/ping.c

@@ -0,0 +1,63 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <arpa/inet.h>
+#include "libp2p/net/p2pnet.h"
+
+#define BUF_SIZE 4096
+
+int ipfs_ping (int argc, char **argv)
+{
+    int socketfd, i, count=10, tcount = 0;
+    uint32_t ipv4;
+    uint16_t port;
+    char b[BUF_SIZE];
+    size_t len;
+    struct timeval time;
+    long cur_time, old_time;
+    double ms, total = 0;
+
+    if (inet_pton (AF_INET, argv[2], &ipv4) == 0) {
+        fprintf(stderr, "Unable to use '%s' as an IP address.\n", argv[1]);
+        return 1;
+    }
+
+    if ((port = atoi(argv[3])) == 0) {
+        fprintf(stderr, "Unable to use '%s' port.\n", argv[2]);
+        return 1;
+    }
+
+    if ((socketfd = socket_tcp4()) <= 0) {
+        perror("can't create socket");
+        return 1;
+    }
+
+    if (socket_connect4(socketfd, ipv4, port) < 0) {
+        perror("fail to connect");
+        return 1;
+    }
+
+    fprintf(stderr, "PING %s.\n", argv[2]);
+
+    for (i=0 ; i < count ; i++) {
+        if (gettimeofday (&time, 0)) return -1;
+        old_time = 1000000 * time.tv_sec + time.tv_usec;
+
+        socket_write(socketfd, "ping", 4, 0);
+        len = socket_read(socketfd, b, sizeof(b), 0);
+
+        if (len == 4 && memcmp(b, "pong", 4) == 0) {
+            if (gettimeofday (&time, 0)) return -1;
+            cur_time = 1000000 * time.tv_sec + time.tv_usec;
+            ms = (cur_time - old_time) / 1000.0;
+            total += ms; tcount++;
+            fprintf(stderr, "Pong received: time=%.2f ms\n", ms);
+        }
+        sleep (1);
+    }
+    fprintf(stderr, "Average latency: %.2fms\n", total / tcount);
+
+    return 0;
+}