7.5.3 Listing the ciphersuites in a priority string

This is a small program to list the enabled ciphersuites by a priority string.

/* This example code is placed in the public domain. */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <gnutls/gnutls.h>

static void print_cipher_suite_list(const char *priorities)
{
	size_t i;
	int ret;
	unsigned int idx;
	const char *name;
	const char *err;
	unsigned char id[2];
	gnutls_protocol_t version;
	gnutls_priority_t pcache;

	if (priorities != NULL) {
		printf("Cipher suites for %s\n", priorities);

		ret = gnutls_priority_init(&pcache, priorities, &err);
		if (ret < 0) {
			fprintf(stderr, "Syntax error at: %s\n", err);
			exit(1);
		}

		for (i = 0;; i++) {
			ret = gnutls_priority_get_cipher_suite_index(pcache, i,
								     &idx);
			if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
				break;
			if (ret == GNUTLS_E_UNKNOWN_CIPHER_SUITE)
				continue;

			name = gnutls_cipher_suite_info(idx, id, NULL, NULL,
							NULL, &version);

			if (name != NULL)
				printf("%-50s\t0x%02x, 0x%02x\t%s\n", name,
				       (unsigned char)id[0],
				       (unsigned char)id[1],
				       gnutls_protocol_get_name(version));
		}

		return;
	}
}

int main(int argc, char **argv)
{
	if (argc > 1)
		print_cipher_suite_list(argv[1]);
	return 0;
}