Initial implementation of routing/kademlia

Makefile

@@ -2,7 +2,7 @@
 DEBUG = true
 export DEBUG
 
-OBJS = crypto/*.o crypto/encoding/*.o thirdparty/mbedtls/*.o hashmap/hashmap.o record/*.o
+OBJS = crypto/*.o crypto/encoding/*.o thirdparty/mbedtls/*.o hashmap/hashmap.o record/*.o routing/*.o
 
 
 compile: 
@@ -10,6 +10,7 @@ compile:
 	cd thirdparty; make all;
 	cd hashmap; make all;
 	cd record; make all;
+	cd routing; make all;
 	ar rcs libp2p.a $(OBJS)
 	
 test: compile
@@ -25,5 +26,6 @@ clean:
 	cd thirdparty; make clean
 	cd test; make clean;
 	cd record; make clean;
+	cd routing; make clean;
 	rm -rf libp2p.a
 

routing/Makefile

@@ -0,0 +1,21 @@
+DHT_DIR = dht
+CC = gcc
+CFLAGS = -O0 -I../include -I$(DHT_DIR) -g3
+LFLAGS =
+DEPS = $(DHT_DIR)/dht.h
+OBJS = kademlia.o dht.o
+
+%.o: %.c $(DEPS)
+	$(CC) -c -o $@ $< $(CFLAGS)
+
+all: $(OBJS)
+
+$(DHT_DIR)/dht.h:
+	git clone https://github.com/jech/dht.git $(DHT_DIR)
+
+dht.c: $(DEPS)
+	ln -s $(DHT_DIR)/dht.c .
+
+clean:
+	rm -f $(OBJS) dht.c
+	rm -rf $(DHT_DIR)

routing/kademlia.c

@@ -0,0 +1,110 @@
+/* For crypt */
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/time.h>
+#include <arpa/inet.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <sys/signal.h>
+#include <libp2p/crypto/sha1.h>
+#include <dht.h>
+
+#define MAX_BOOTSTRAP_NODES 20
+static struct sockaddr_storage bootstrap_nodes[MAX_BOOTSTRAP_NODES];
+static int num_bootstrap_nodes = 0;
+
+/* The call-back function is called by the DHT whenever something
+   interesting happens.  Right now, it only happens when we get a new value or
+   when a search completes, but this may be extended in future versions. */
+static void
+callback(void *closure,
+         int event,
+         const unsigned char *info_hash,
+         const void *data, size_t data_len)
+{
+    switch (event) {
+        case DHT_EVENT_VALUES:
+        case DHT_EVENT_VALUES6:
+            printf("Received %d values.\n", (int)(data_len / 6));
+            break;
+        case DHT_EVENT_SEARCH_DONE:
+        case DHT_EVENT_SEARCH_DONE6:
+            printf("Search done.\n");
+            break;
+        default:
+            break;
+    }
+}
+
+/* Functions called by the DHT. */
+
+int dht_blacklisted (const struct sockaddr *sa, int salen)
+{
+    return 0;
+}
+
+/* We need to provide a reasonably strong cryptographic hashing function.
+   SHA-1 code adapted from https://github.com/mwarning/KadNode */
+void dht_hash (void *hash_return, int hash_size,
+               const void *v1, int len1,
+               const void *v2, int len2,
+               const void *v3, int len3)
+{
+    SHA1_CTX ctx;
+    uint8_t digest[SHA1_DIGEST_SIZE];
+
+    SHA1_Init (&ctx);
+    if (v1) SHA1_Update (&ctx, v1, len1);
+    if (v2) SHA1_Update (&ctx, v2, len2);
+    if (v3) SHA1_Update (&ctx, v3, len3);
+    SHA1_Final (&ctx, digest);
+
+    if (hash_size > SHA1_DIGEST_SIZE) {
+        memset ((char*)hash_return + SHA1_DIGEST_SIZE, 0, hash_size - SHA1_DIGEST_SIZE);
+        hash_size = SHA1_DIGEST_SIZE;
+    }
+    memcpy(hash_return, digest, hash_size);
+}
+
+int dht_random_bytes (void *buf, size_t size)
+{
+    int fd, rc, save;
+    size_t len = 0;
+
+    fd = open("/dev/urandom", O_RDONLY);
+    if (fd < 0) {
+        return fd;
+    }
+
+    while (len < size) {
+        rc = read (fd, buf + len, size - len);
+        if (rc < 0) {
+            if (errno == EINTR || errno == EAGAIN) {
+                continue; // not fatal, try again.
+            }
+            if (errno == EWOULDBLOCK && len > 0) {
+                rc = len;
+            }
+
+            break; // fail.
+        }
+        len += rc;
+    }
+
+    if (len > 0 && rc >= 0) {
+        rc = len;
+    }
+
+    save = errno;
+    close(fd);
+    errno = save;
+
+    return rc;
+}