[WIP] wg: Support human-readable peer names

TODO:
* Refactor the inflatable_buffer code from ipc.c and use it for both
  the wgpeer_name array and the names.
* ugly_print, dumb_print
* Make wgpeer_names part of wgdevice?
* Check for dupes?
* Test!

Signed-off-by: Luis Ressel <aranea@aixah.de>

src/tools/peer_names.c

@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Luis Ressel <aranea@aixah.de>. All Rights Reserved.
+ */
+
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "containers.h"
+#include "encoding.h"
+#include "peer_names.h"
+
+static bool parse_peer_name(char *line, struct wgpeer_name *slot)
+{
+	char *name;
+	size_t len;
+
+	name = strpbrk(line, " \t");
+	if (!name)
+		return false;
+	*name = '\0';
+
+	if (!key_from_base64(slot->public_key, line))
+		return false;
+
+	len = strlen(++name);
+	if (name[len - 1] == '\n')
+		name[len - 1] = '\0';
+	slot->name = strdup(name);
+	return !!slot->name;
+}
+
+static int peer_name_cmp(const void *a, const void *b)
+{
+	const struct wgpeer_name *x = a, *y = b;
+	return memcmp(x->public_key, y->public_key, WG_KEY_LEN);
+}
+
+bool peer_names_open(struct wgpeer_names *names, struct wgdevice *device)
+{
+	size_t max_peers = 1, peers = 0, buf_len = 0, path_len;
+	struct wgpeer_name *arr, *arr2;
+	char *buf = NULL, *path;
+	FILE *f;
+
+	path = getenv("WG_PEER_NAMES");
+	if (!path || !path[0]) {
+		errno = 0;
+		return false;
+	}
+
+	path_len = strlen(path);
+	if (path[path_len - 1] == '/') {
+		size_t dev_len = strlen(device->name);
+		char *path2 = malloc(path_len + dev_len + 1);
+
+		if (!path2)
+			return false;
+		memcpy(path2, path, path_len);
+		memcpy(path2 + path_len, device->name, dev_len + 1);
+		f = fopen(path2, "r");
+		free(path2);
+	} else
+		f = fopen(path, "r");
+	if (!f)
+		return false;
+
+	arr = malloc(sizeof(struct wgpeer_name));
+	if (!arr)
+		return false;
+
+	while (getline(&buf, &buf_len, f) >= 0) {
+		if (parse_peer_name(buf, &arr[peers]) && (++peers == max_peers)) {
+			// TODO: Pulled this overflow check out of my ass, gotta revisit it later
+			if (SIZE_MAX / (2 * sizeof(struct wgpeer_name)) < max_peers) {
+				errno = ENOMEM;
+				return false;
+			}
+			max_peers *= 2;
+
+			arr2 = realloc(arr, max_peers * sizeof(struct wgpeer_name));
+			if (!arr2) {
+				free(arr);
+				return false;
+			}
+			arr = arr2;
+		}
+	}
+	free(buf);
+
+	if (!peers)
+		free(arr);
+	if ((arr2 = realloc(arr, peers * sizeof(struct wgpeer_name))))
+		arr = arr2;
+
+	qsort(arr, peers, sizeof(struct wgpeer_name), peer_name_cmp);
+	names->len = peers;
+	names->arr = arr;
+	return true;
+}
+
+void peer_names_free(struct wgpeer_names *names)
+{
+	if (!names)
+		return;
+
+	for (size_t i = 0; i < names->len; ++i)
+		free(names->arr[i].name);
+	if (names->len)
+		free(names->arr);
+}
+
+char *peer_names_get(struct wgpeer_names *names, uint8_t key[static WG_KEY_LEN])
+{
+	size_t r, l = 0;
+
+	if (!names || !names->len)
+		return NULL;
+	r = names->len - 1;
+
+	while (l <= r) {
+		size_t m = l + (r - l) / 2;
+		int cmp = memcmp(key, names->arr[m].public_key, WG_KEY_LEN);
+		if (!cmp)
+			return names->arr[m].name;
+		else if (cmp > 0)
+			l = m + 1;
+		else if (!m)
+			break;
+		else
+			r = m - 1;
+	}
+	return NULL;
+}

src/tools/peer_names.h

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Luis Ressel <aranea@aixah.de>. All Rights Reserved.
+ */
+
+#ifndef PEER_NAMES_H
+#define PEER_NAMES_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "containers.h"
+
+struct wgpeer_name {
+	char *name;
+	uint8_t public_key[WG_KEY_LEN];
+};
+
+struct wgpeer_names {
+	size_t len;
+	struct wgpeer_name *arr;
+};
+
+bool peer_names_open(struct wgpeer_names *names, struct wgdevice *device);
+void peer_names_free(struct wgpeer_names *names);
+char *peer_names_get(struct wgpeer_names *names, uint8_t key[static WG_KEY_LEN]);
+
+#endif // PEER_NAMES_H

src/tools/show.c

@@ -22,6 +22,7 @@
 #include "ipc.h"
 #include "terminal.h"
 #include "encoding.h"
+#include "peer_names.h"
 #include "subcommands.h"
 
 static int peer_cmp(const void *first, const void *second)
@@ -205,8 +206,9 @@ static void show_usage(void)
 	fprintf(stderr, "Usage: %s %s { <interface> | all | interfaces } [public-key | private-key | listen-port | fwmark | peers | preshared-keys | endpoints | allowed-ips | latest-handshakes | transfer | persistent-keepalive | dump]\n", PROG_NAME, COMMAND_NAME);
 }
 
-static void pretty_print(struct wgdevice *device)
+static void pretty_print(struct wgdevice *device, struct wgpeer_names *names)
 {
+	char *name;
 	struct wgpeer *peer;
 	struct wgallowedip *allowedip;
 
@@ -226,6 +228,8 @@ static void pretty_print(struct wgdevice *device)
 	}
 	for_each_wgpeer(device, peer) {
 		terminal_printf(TERMINAL_FG_YELLOW TERMINAL_BOLD "peer" TERMINAL_RESET ": " TERMINAL_FG_YELLOW "%s" TERMINAL_RESET "\n", key(peer->public_key));
+		if ((name = peer_names_get(names, peer->public_key)))
+			terminal_printf("  " TERMINAL_BOLD "name" TERMINAL_RESET ": %s\n", name);
 		if (peer->flags & WGPEER_HAS_PRESHARED_KEY)
 			terminal_printf("  " TERMINAL_BOLD "preshared key" TERMINAL_RESET ": %s\n", masked_key(peer->preshared_key));
 		if (peer->endpoint.addr.sa_family == AF_INET || peer->endpoint.addr.sa_family == AF_INET6)
@@ -398,6 +402,7 @@ int show_main(int argc, char *argv[])
 		interface = interfaces;
 		for (size_t len = 0; (len = strlen(interface)); interface += len + 1) {
 			struct wgdevice *device = NULL;
+			struct wgpeer_names names;
 
 			if (ipc_get_device(&device, interface) < 0) {
 				fprintf(stderr, "Unable to access interface %s: %s\n", interface, strerror(errno));
@@ -410,9 +415,12 @@ int show_main(int argc, char *argv[])
 					break;
 				}
 			} else {
-				pretty_print(device);
+				if (!peer_names_open(&names, device) && errno)
+					perror("peer_names_open");
+				pretty_print(device, &names);
 				if (strlen(interface + len + 1))
 					printf("\n");
+				peer_names_free(&names);
 			}
 			free_wgdevice(device);
 			ret = 0;
@@ -438,6 +446,7 @@ int show_main(int argc, char *argv[])
 		show_usage();
 	else {
 		struct wgdevice *device = NULL;
+		struct wgpeer_names names;
 
 		if (ipc_get_device(&device, argv[1]) < 0) {
 			perror("Unable to access interface");
@@ -446,8 +455,12 @@ int show_main(int argc, char *argv[])
 		if (argc == 3) {
 			if (!ugly_print(device, argv[2], false))
 				ret = 1;
-		} else
-			pretty_print(device);
+		} else {
+			if (!peer_names_open(&names, device) && errno)
+				perror("peer_names_open");
+			pretty_print(device, &names);
+			peer_names_free(&names);
+		}
 		free_wgdevice(device);
 	}
 	return ret;