118 lines
3.1 KiB
Text
118 lines
3.1 KiB
Text
This allow switching the hashing algorithm (between a crypt(3)-based
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one and MD5) at run-time, rather than at compile-time.
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-mi
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--- dht-example.c 2014-05-03 14:37:50.000000000 -0400
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+++ dht-example.c 2014-05-04 21:34:58.000000000 -0400
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@@ -12,4 +12,5 @@
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#include <fcntl.h>
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#include <sys/time.h>
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+#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <sys/types.h>
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@@ -17,4 +18,7 @@
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#include <netdb.h>
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#include <sys/signal.h>
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+#include <signal.h>
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+#include <unistd.h>
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+#include <md5.h>
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#include "dht.h"
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@@ -91,4 +95,11 @@
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static unsigned char buf[4096];
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+typedef void (hashing_method)(void *, int,
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+ const void *, int,
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+ const void *, int,
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+ const void *, int);
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+
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+static hashing_method *hasher, crypt_hash, md5_hash;
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+
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int
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main(int argc, char **argv)
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@@ -112,9 +123,8 @@
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memset(&sin6, 0, sizeof(sin6));
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sin6.sin6_family = AF_INET6;
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-
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-
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+ hasher = crypt_hash;
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while(1) {
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- opt = getopt(argc, argv, "q46b:i:");
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+ opt = getopt(argc, argv, "q46b:i:m");
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if(opt < 0)
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break;
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@@ -143,4 +153,6 @@
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id_file = optarg;
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break;
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+ case 'm':
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+ hasher = md5_hash;
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default:
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goto usage;
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@@ -405,6 +417,7 @@
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usage:
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- printf("Usage: dht-example [-q] [-4] [-6] [-i filename] [-b address]...\n"
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- " port [address port]...\n");
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+ printf("Usage: dht-example [-q] [-4] [-6] [-i filename] [-b address] [-m]\n"
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+ " port [address port]...\n"
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+ "(Use -m to use MD5 digest instead of crypt()-based one)\n");
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exit(1);
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}
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@@ -420,25 +433,28 @@
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/* We need to provide a reasonably strong cryptographic hashing function.
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Here's how we'd do it if we had RSA's MD5 code. */
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-#if 0
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-void
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-dht_hash(void *hash_return, int hash_size,
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+static void
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+md5_hash(void *hash_return, int hash_size,
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const void *v1, int len1,
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const void *v2, int len2,
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const void *v3, int len3)
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{
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- static MD5_CTX ctx;
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+ MD5_CTX ctx;
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MD5Init(&ctx);
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MD5Update(&ctx, v1, len1);
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MD5Update(&ctx, v2, len2);
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MD5Update(&ctx, v3, len3);
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- MD5Final(&ctx);
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- if(hash_size > 16)
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- memset((char*)hash_return + 16, 0, hash_size - 16);
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- memcpy(hash_return, ctx.digest, hash_size > 16 ? 16 : hash_size);
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+ if (hash_size >= 16) {
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+ MD5Final(hash_return, &ctx);
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+ if(hash_size > 16)
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+ memset((char*)hash_return + 16, 0, hash_size - 16);
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+ } else {
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+ unsigned char digest[16];
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+ MD5Final(digest, &ctx);
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+ memcpy(hash_return, digest, hash_size);
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+ }
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}
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-#else
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/* But for this example, we might as well use something weaker. */
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-void
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-dht_hash(void *hash_return, int hash_size,
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+static void
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+crypt_hash(void *hash_return, int hash_size,
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const void *v1, int len1,
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const void *v2, int len2,
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@@ -460,5 +476,14 @@
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strncpy(hash_return, crypt(key, "jc"), hash_size);
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}
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-#endif
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+
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+void
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+dht_hash(void *hash_return, int hash_size,
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+ const void *v1, int len1,
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+ const void *v2, int len2,
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+ const void *v3, int len3)
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+{
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+ hasher(hash_return, hash_size, v1, len1,
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+ v2, len2, v3, len3);
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+}
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int
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