TOX-DNS V1 name resolution.

Added Tox DNS resolution via libldns. No DNSSEC yet. Only Tox DNS
 version 1 resolution.

 Added new development command /dns to test name resolution.

CMakeLists.txt

@@ -26,11 +26,16 @@ set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})
 find_package(WeeChat REQUIRED)
 find_package(Tox REQUIRED
     COMPONENTS CORE
-    OPTIONAL_COMPONENTS AV ENCRYPTSAVE)
+    OPTIONAL_COMPONENTS AV ENCRYPTSAVE DNS)
+find_package(Ldns)
 
 set(PLUGIN_PATH "lib/weechat/plugins" CACHE PATH
     "Path to install the plugin binary to.")
 
+if(Ldns_FOUND AND Tox_DNS_FOUND)
+    list(APPEND DNS_SRCS src/twc-dns.c)
+endif()
+
 add_library(tox MODULE
     src/twc.c
     src/twc-bootstrap.c
@@ -38,6 +43,7 @@ add_library(tox MODULE
     src/twc-commands.c
     src/twc-completion.c
     src/twc-config.c
+    ${DNS_SRCS}
     src/twc-friend-request.c
     src/twc-gui.c
     src/twc-group-invite.c
@@ -53,8 +59,9 @@ set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99 -Wall -Wextra -Wno-unused-paramet
 
 include_directories(${Tox_INCLUDE_DIRS})
 include_directories(${WeeChat_INCLUDE_DIRS})
+include_directories(${Ldns_INCLUDE_DIRS})
 
-target_link_libraries(tox ${Tox_LIBRARIES})
+target_link_libraries(tox ${Tox_LIBRARIES} ${Ldns_LIBRARIES})
 
 if(Tox_AV_FOUND)
     add_definitions(-DTOXAV_ENABLED)
@@ -64,8 +71,11 @@ if(Tox_ENCRYPTSAVE_FOUND)
     add_definitions(-DTOXENCRYPTSAVE_ENABLED)
 endif()
 
+if(Ldns_FOUND AND Tox_DNS_FOUND)
+    add_definitions(-DLDNS_ENABLED)
+endif()
+
 # remove lib prefix (libtox.so -> tox.so)
 set_target_properties(tox PROPERTIES PREFIX "")
 
 install(TARGETS tox DESTINATION "${PLUGIN_PATH}")
-

cmake/FindLdns.cmake

@@ -0,0 +1,14 @@
+set(Ldns_INCLUDE_DIRS)
+set(Ldns_LIBRARIES)
+
+find_path(Ldns_INCLUDE_DIR ldns/ldns.h)
+find_library(Ldns_LIBRARY ldns)
+
+if (Ldns_INCLUDE_DIR AND Ldns_LIBRARY)
+    set(Ldns_FOUND TRUE)
+    list(APPEND Ldns_LIBRARIES ldns)
+    list(APPEND Ldns_INCLUDE_DIRS ${Ldns_INCLUDE_DIR})
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(Ldns FOUND_VAR Ldns_FOUND REQUIRED_VARS Ldns_INCLUDE_DIRS Ldns_LIBRARIES)

src/twc-commands.c

@@ -27,6 +27,7 @@
 #include "twc-list.h"
 #include "twc-profile.h"
 #include "twc-chat.h"
+#include "twc-dns.h"
 #include "twc-friend-request.h"
 #include "twc-group-invite.h"
 #include "twc-bootstrap.h"
@@ -41,6 +42,15 @@ enum TWC_FRIEND_MATCH
     TWC_FRIEND_MATCH_NOMATCH = -2,
 };
 
+
+typedef struct
+{
+    const bool force;
+    struct t_twc_profile *profile;
+    char *dns_name;
+    const char *message;
+} t_twc_friend_add_data;
+
 /**
  * Make sure a command is executed on a Tox profile buffer. If not, warn user
  * and abort.
@@ -215,6 +225,165 @@ twc_cmd_bootstrap(void *data, struct t_gui_buffer *buffer,
     return WEECHAT_RC_ERROR;
 }
 
+#ifdef LDNS_ENABLED
+void
+twc_cmd_dns_cb(void *data, enum t_twc_dns_rc rc, const uint8_t *tox_id)
+{
+    if (!rc == TWC_DNS_RC_OK)
+    {
+	weechat_printf(weechat_current_buffer(), "%s Error resolving Tox DNS ID (%d).",
+		       weechat_prefix("error"), rc);
+	return;
+    }
+    char toxid[TOX_ADDRESS_SIZE * 2 + 1];
+    twc_bin2hex(tox_id, TOX_ADDRESS_SIZE, toxid);
+    toxid[TOX_ADDRESS_SIZE * 2] = 0;
+    weechat_printf(weechat_current_buffer(), "Resolved Tox DNS ID to %s", toxid);
+}
+
+/**
+ * Command /dns callback.
+ */
+int
+twc_cmd_dns(void *data, struct t_gui_buffer *buffer,
+	    int argc, char **argv, char**argv_eol)
+{
+    if (argc == 1)
+	return WEECHAT_RC_ERROR;
+
+    struct t_twc_profile *profile = twc_profile_search_buffer(buffer);
+    TWC_CHECK_PROFILE(profile);
+    TWC_CHECK_PROFILE_LOADED(profile);
+
+    char dns_id[TWC_DNS_ID_MAXLEN + 1];
+    snprintf(dns_id, TWC_DNS_ID_MAXLEN, "%s", argv_eol[1]);
+    enum t_twc_dns_rc dns_rc;
+    dns_rc = twc_dns_query(dns_id, &twc_cmd_dns_cb, NULL);
+    if (dns_rc)
+    {
+	weechat_printf(buffer, "%sResolving TOX-DNS ID. Error code %d",
+		       weechat_prefix("error"), dns_rc);
+	return WEECHAT_RC_ERROR;
+    }
+    return WEECHAT_RC_OK;
+}
+#endif // LDNS_ENABLED
+
+/**
+ * Sub-command '/friend add' callback.
+ */
+static void
+twc_cmd_friend_add_cb(void *data, enum t_twc_dns_rc rc, const uint8_t *tox_id)
+{
+    const t_twc_friend_add_data *d = data;
+    const bool force = d->force;
+    char *name = d->dns_name;
+    struct t_twc_profile *profile = d->profile;
+    const char *message = d->message;
+    char toxid[TOX_ADDRESS_SIZE * 2 + 1];
+
+    switch (rc)
+    {
+        case TWC_DNS_RC_OK:
+            break;
+        case TWC_DNS_RC_VERSION:
+            weechat_printf(profile->buffer,
+                           "%sUnsupported Tox DNS version in reply.",
+                           weechat_prefix("error"));
+            return;
+        case TWC_DNS_RC_ERROR:
+            weechat_printf(profile->buffer, "%sCould not resolve Tox ID.",
+                           weechat_prefix("error"));
+            return;
+        case TWC_DNS_RC_EINVAL:
+            weechat_printf(profile->buffer, "%sInvalid Tox DNS ID.",
+                           weechat_prefix("error"));
+            return;
+        default:
+            weechat_printf(profile->buffer,
+                           "%sUnknown error resolving Tox ID (%d).",
+                           weechat_prefix("error"), rc);
+            return;
+    }
+    twc_bin2hex(tox_id, TOX_ADDRESS_SIZE, toxid);
+    toxid[TOX_ADDRESS_SIZE * 2] = 0;
+    weechat_printf(profile->buffer, "Resolved tox dns id '%s' to %s", name,  toxid);
+    free(name);
+
+    /* -force to delete friend before sending a new friend request */
+    if (force)
+    {
+        bool fail = false;
+        char *hex_key = strndup(toxid, TOX_PUBLIC_KEY_SIZE * 2);
+        int32_t friend_number = twc_match_friend(profile, hex_key);
+        free(hex_key);
+
+        if (friend_number == TWC_FRIEND_MATCH_AMBIGUOUS)
+            fail = true;
+        else if (friend_number != TWC_FRIEND_MATCH_NOMATCH)
+            fail = !tox_friend_delete(profile->tox, friend_number, NULL);
+
+        if (fail)
+        {
+            weechat_printf(profile->buffer,
+                           "%scould not remove friend; please remove "
+                           "manually before resending friend request",
+                           weechat_prefix("error"));
+            return;
+        }
+    }
+
+    TOX_ERR_FRIEND_ADD err;
+    (void)tox_friend_add(profile->tox,
+                         (uint8_t *)tox_id,
+                         (uint8_t *)message,
+                         strlen(message), &err);
+
+    switch (err)
+    {
+        case TOX_ERR_FRIEND_ADD_OK:
+            weechat_printf(profile->buffer,
+                           "%sFriend request sent!",
+                           weechat_prefix("network"));
+            break;
+        case TOX_ERR_FRIEND_ADD_TOO_LONG:
+            weechat_printf(profile->buffer,
+                           "%sFriend request message too long! Try again.",
+                           weechat_prefix("error"));
+            break;
+        case TOX_ERR_FRIEND_ADD_ALREADY_SENT:
+        case TOX_ERR_FRIEND_ADD_SET_NEW_NOSPAM:
+            weechat_printf(profile->buffer,
+                           "%sYou have already sent a friend request to "
+                           "that address (use -force to circumvent)",
+                           weechat_prefix("error"));
+            break;
+        case TOX_ERR_FRIEND_ADD_OWN_KEY:
+            weechat_printf(profile->buffer,
+                           "%sYou can't add yourself as a friend.",
+                           weechat_prefix("error"));
+            break;
+        case TOX_ERR_FRIEND_ADD_BAD_CHECKSUM:
+            weechat_printf(profile->buffer,
+                           "%sInvalid friend address - try again.",
+                           weechat_prefix("error"));
+            break;
+        case TOX_ERR_FRIEND_ADD_MALLOC:
+            weechat_printf(profile->buffer,
+                           "%sCould not add friend (out of memory).",
+                           weechat_prefix("error"));
+            break;
+        case TOX_ERR_FRIEND_ADD_NULL:
+        case TOX_ERR_FRIEND_ADD_NO_MESSAGE: /* this should not happen as we
+                                               validate the message */
+        default:
+            weechat_printf(profile->buffer,
+                           "%sCould not add friend (unknown error %d).",
+                           weechat_prefix("error"), err);
+            break;
+    }
+}
+
 /**
  * Command /friend callback.
  */
@@ -286,89 +455,48 @@ twc_cmd_friend(void *data, struct t_gui_buffer *buffer,
         if (!message)
             message = weechat_config_string(twc_config_friend_request_message);
 
+	/* strip "tox:" URI prefix */
+	char *l = weechat_strcasestr(hex_id, "tox:");
+	if (l && (l == hex_id))
+	    hex_id = &hex_id[4];
+
+        char *dns_name = strdup(hex_id);
+        if (!dns_name)
+        {
+            weechat_printf(profile->buffer,
+                           "%sMemory allocation error.",
+                           weechat_prefix("error"));
+            return WEECHAT_RC_OK;
+        }
+        t_twc_friend_add_data data = { force, profile, dns_name, message };
+        uint8_t address[TOX_ADDRESS_SIZE];
+
         if (strlen(hex_id) != TOX_ADDRESS_SIZE * 2)
         {
+#ifdef LDNS_ENABLED
+            /* resolve toxid */
+	    enum t_twc_dns_rc dns_rc;
+	    dns_rc = twc_dns_query(hex_id, &twc_cmd_friend_add_cb, &data);
+	    if (dns_rc)
+	    {
 		weechat_printf(profile->buffer,
-                           "%sTox ID length invalid. Please try again.",
+			       "%sError calling Tox DNS resolver (%d).",
+			       weechat_prefix("error"), dns_rc);
+	    }
+#else
+            /* immediately fail */
+            weechat_printf(profile->buffer,
+                           "%sTox ID length invalid and Tox DNS resolution not implemented."
+                           " Please try again.",
                            weechat_prefix("error"));
-
+#endif // LDNS_ENABLED
             return WEECHAT_RC_OK;
         }
 
-        uint8_t address[TOX_ADDRESS_SIZE];
         twc_hex2bin(hex_id, TOX_ADDRESS_SIZE, address);
+        /* call the callback by hand and finish the /friend add command */
+        twc_cmd_friend_add_cb(&data, TWC_DNS_RC_OK, address);
 
-        if (force)
-        {
-            bool fail = false;
-            char *hex_key = strndup(hex_id, TOX_PUBLIC_KEY_SIZE * 2);
-            int32_t friend_number = twc_match_friend(profile, hex_key);
-            free(hex_key);
-
-            if (friend_number == TWC_FRIEND_MATCH_AMBIGUOUS)
-                fail = true;
-            else if (friend_number != TWC_FRIEND_MATCH_NOMATCH)
-                fail = !tox_friend_delete(profile->tox, friend_number, NULL);
-
-            if (fail)
-            {
-                weechat_printf(profile->buffer,
-                               "%scould not remove friend; please remove "
-                               "manually before resending friend request",
-                               weechat_prefix("error"));
-                return WEECHAT_RC_OK;
-            }
-        }
-
-        TOX_ERR_FRIEND_ADD err;
-        (void)tox_friend_add(profile->tox,
-                                         (uint8_t *)address,
-                                         (uint8_t *)message,
-                                         strlen(message), &err);
-
-        switch (err)
-        {
-            case TOX_ERR_FRIEND_ADD_OK:
-                weechat_printf(profile->buffer,
-                               "%sFriend request sent!",
-                               weechat_prefix("network"));
-                break;
-            case TOX_ERR_FRIEND_ADD_TOO_LONG:
-                weechat_printf(profile->buffer,
-                               "%sFriend request message too long! Try again.",
-                               weechat_prefix("error"));
-                break;
-            case TOX_ERR_FRIEND_ADD_ALREADY_SENT:
-            case TOX_ERR_FRIEND_ADD_SET_NEW_NOSPAM:
-                weechat_printf(profile->buffer,
-                               "%sYou have already sent a friend request to "
-                               "that address (use -force to circumvent)",
-                               weechat_prefix("error"));
-                break;
-            case TOX_ERR_FRIEND_ADD_OWN_KEY:
-                weechat_printf(profile->buffer,
-                               "%sYou can't add yourself as a friend.",
-                               weechat_prefix("error"));
-                break;
-            case TOX_ERR_FRIEND_ADD_BAD_CHECKSUM:
-                weechat_printf(profile->buffer,
-                               "%sInvalid friend address - try again.",
-                               weechat_prefix("error"));
-                break;
-            case TOX_ERR_FRIEND_ADD_MALLOC:
-                weechat_printf(profile->buffer,
-                               "%sCould not add friend (out of memory).",
-                               weechat_prefix("error"));
-                break;
-            case TOX_ERR_FRIEND_ADD_NULL:
-            case TOX_ERR_FRIEND_ADD_NO_MESSAGE: /* this should not happen as we
-                                                   validate the message */
-            default:
-                weechat_printf(profile->buffer,
-                               "%sCould not add friend (unknown error %d).",
-                               weechat_prefix("error"), err);
-                break;
-        }
 
         return WEECHAT_RC_OK;
     }
@@ -668,6 +796,7 @@ twc_cmd_me(void *data, struct t_gui_buffer *buffer,
 
     return WEECHAT_RC_OK;
 }
+
 /**
  * Command /msg callback.
  */
@@ -1208,6 +1337,13 @@ twc_commands_init()
                          "<message>",
                          "message: message to send",
                          NULL, twc_cmd_me, NULL);
+#ifdef LDNS_ENABLED
+    weechat_hook_command("dns",
+			 "test toxdns",
+			 "<toxdnsid>",
+			 "[tox:]<name>[@|._tox.]<domain>\n",
+			 NULL, twc_cmd_dns, NULL);
+#endif // LDNS_ENABLED
 
     weechat_hook_command("msg",
                          "send a message to a Tox friend",

src/twc-dns.c

@@ -1,5 +1,6 @@
 /*
- * Copyright (c) 2015 Håvard Pettersson <mail@haavard.me>
+ * Copyright (c) 2015 Håvard Pettersson <mail@haavard.me>,
+ *                    Michael Raitza <spacefrogg-devel@meterriblecrew.net>
  *
  * This file is part of Tox-WeeChat.
  *
@@ -21,10 +22,14 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 
 #include <weechat/weechat-plugin.h>
 #include <tox/tox.h>
 
+#include <ldns/ldns.h>
+#undef dprintf /* well, yeah, well... */
+
 #include "twc.h"
 #include "twc-utils.h"
 
@@ -43,6 +48,312 @@ struct t_twc_dns_callback_info
     struct t_hook *hook;
 };
 
+/**
+ * Struct holding the split dns_id.
+ */
+typedef struct
+{
+    char *name;
+    char *domain;
+} t_twc_toxdns_data;
+
+/**
+ * Struct holding a list of DNS responses.
+ */
+typedef struct
+{
+    size_t count;
+    uint8_t **data;  
+} t_resolve_response_list;
+
+static t_twc_toxdns_data *
+toxdns_data_new(size_t namelen, size_t domlen)
+{
+    t_twc_toxdns_data *d;
+    d = (t_twc_toxdns_data *)malloc(sizeof(t_twc_toxdns_data)
+				    + namelen + domlen + 2);
+    if (!d)
+	return NULL;
+    d->name = (char *)malloc(namelen + 1);
+    if (!d->name)
+    {
+	free(d);
+	return NULL;
+    }
+    d->domain = (char *)malloc(domlen + 1);
+    if (!d->domain)
+    {
+	free(d);
+	free(d->name);
+	return NULL;
+    }
+    return d;
+}
+
+static void
+toxdns_data_deep_free(t_twc_toxdns_data *d)
+{
+    if (d)
+    {
+	if (d->name)
+	    free(d->name);
+	if (d->domain)
+	    free(d->domain);
+	free(d);
+    }
+}
+
+/**
+ * Splits [tox:]<name>[@|._tox.]<domain> into a struct S with two
+ * fields S.name = "<name>" and S.domain = "_tox.<domain>.". Note the
+ * ending dot that finalises the DNS domain for later query!
+ *
+ * name: a string that is shorter than or equal to RESOLVE_ID_MAXLEN
+ *       and must be in the form mentioned above.
+ */
+static t_twc_toxdns_data *
+split_name(const char *name, enum t_twc_dns_rc *error)
+{
+    enum t_twc_dns_rc err = TWC_DNS_RC_OK;
+    t_twc_toxdns_data *data = NULL;
+    uint32_t name_len = strlen(name);
+    char n[name_len + 1];
+    char d[name_len + 6];
+    char *domain;
+    char *d_pos = d;
+    char *n_pos = n;
+
+    strcpy(n, name);
+    domain = strstr(n, "tox:");  /* ignore a "tox:" uri prefix */
+    if (domain && (domain == n))
+	n_pos = &n[4];
+
+    domain = strstr(n_pos, "._tox.");
+    if ((!domain) || (domain == n_pos) || (strlen(domain) <= 6))
+    {
+	domain = strstr(n_pos, "@");
+	if ((!domain) || (domain == n_pos) || (strlen(domain) <= 1))
+	{
+	    err = TWC_DNS_RC_EINVAL;
+	    goto err;
+	}
+	d_pos = stpcpy(d_pos, "_tox.");
+    }
+    d_pos = stpcpy(d_pos, &domain[1]);
+    strcpy(d_pos, ".");
+    domain[0] = 0;
+
+    data = toxdns_data_new(strlen(n_pos), strlen(d));
+    if (!data)
+    {
+	err = TWC_DNS_RC_ERROR;
+	goto err;
+    }
+    strcpy(data->name, n_pos);
+    strcpy(data->domain, d);
+
+  err:
+    *error = err;
+    return data;
+}
+
+static size_t
+resolve_response_count(const t_resolve_response_list *resp)
+{
+    if (resp)
+	return resp->count;
+    return 0;
+}
+
+static uint8_t *
+resolve_response_data(const t_resolve_response_list *resp, const size_t nr)
+{
+    if (nr < resolve_response_count(resp))
+	return resp->data[nr];
+    return NULL;
+}
+
+static t_resolve_response_list *
+resolve_response_list_new(size_t size)
+{
+    t_resolve_response_list *resps;
+    resps = (t_resolve_response_list *)malloc(sizeof(t_resolve_response_list)
+					      + sizeof(char*) * size);
+    if (!resps)
+	return NULL;
+    resps->count = 0;
+    resps->data = (uint8_t **)&resps->data + 1;
+    return resps;
+}
+
+static void
+resolve_response_list_deep_free(t_resolve_response_list *resp)
+{
+    if (!resp)
+	return;
+    for (size_t i = 0; i < resolve_response_count(resp); ++i)
+	if (resp->data[i])
+	    free(resp->data[i]);
+    free(resp);
+}
+
+static ldns_rr_list *
+twc_ldns_query(ldns_resolver* res, const char *name, const ldns_rr_type t,
+	       enum t_twc_dns_rc *err)
+{
+    ldns_rdf *domain = ldns_dname_new_frm_str(name);
+    ldns_pkt *pkt;
+    ldns_rr_list *txt = NULL;
+
+    *err = TWC_DNS_RC_ERROR;
+
+    if (!domain)
+	goto err_dom;
+
+    for (size_t i = 0; i < ldns_resolver_nameserver_count(res); ++i)
+    {
+        pkt = ldns_resolver_query(res, domain, t, LDNS_RR_CLASS_IN, LDNS_RD);
+        if (!pkt)
+            goto fin;
+        switch (ldns_pkt_get_rcode(pkt))
+        {
+            case LDNS_RCODE_NOERROR:
+                *err = TWC_DNS_RC_OK;
+                txt = ldns_pkt_rr_list_by_type(pkt, t, LDNS_SECTION_ANSWER);
+                goto fin;
+            case LDNS_RCODE_REFUSED:
+            case LDNS_RCODE_NXDOMAIN:
+            case LDNS_RCODE_SERVFAIL:
+                for (size_t i = 0; i < ldns_resolver_nameserver_count(res); ++i)
+                    if (!ldns_rdf_compare(ldns_pkt_answerfrom(pkt),
+                                          ldns_resolver_nameservers(res)[i]))
+                    {
+                        /* mark faulty nameserver as unreachable */
+                        ldns_resolver_set_nameserver_rtt(res, i, LDNS_RESOLV_RTT_INF);
+                        break;
+                    }
+                break;
+            default:
+                goto fin;
+        }
+    }
+  fin:
+    ldns_rdf_deep_free(domain);
+    if (pkt)
+	ldns_pkt_free(pkt);
+  err_dom:
+    return txt;
+}
+
+/**
+ * Resolve the TXT records for NAME and return all responses. Outer
+ * quotes are stripped from TXT records. All fields of a TXT record
+ * are stiched together to a long string stripping white space as
+ * requested by protocol.
+ */
+static t_resolve_response_list *
+twc_ldns_resolve(char *name, enum t_twc_dns_rc *err) {
+    ldns_resolver *res;
+    ldns_status s;
+    ldns_rr_list *txt = NULL;
+    t_resolve_response_list *txts = NULL;
+
+    *err= TWC_DNS_RC_OK;
+
+    s = ldns_resolver_new_frm_file(&res, NULL);
+    if (s != LDNS_STATUS_OK)
+    {
+	*err = TWC_DNS_RC_ERROR;
+	goto err;
+    }
+    txt = twc_ldns_query(res, name, LDNS_RR_TYPE_TXT, err);
+    if (!txt)
+	goto err_pkt;
+    txts = resolve_response_list_new(ldns_rr_list_rr_count(txt));
+    if (!txts)
+    {
+	*err = TWC_DNS_RC_ERROR;
+	goto err_txt;
+    }
+
+    for (size_t i = 0; i < ldns_rr_list_rr_count(txt); ++i)
+    {
+	ldns_rr *rr = ldns_rr_list_rr(txt, i);
+	char txt_field[256] = {0}; /* TXT RR RDATA can be 255 bytes long */
+	char *cur_pos = txt_field;
+
+	/* stich together all TXT RR RDATA fields, stripping quotes */
+	for (size_t j = 0; j < ldns_rr_rd_count(rr); ++j)
+	{
+	    char *rdata = ldns_rdf2str(ldns_rr_rdf(rr, j));
+	    size_t len = strlen(rdata);
+
+	    if (rdata[0] == '"')
+	    {
+		rdata[len - 1] = 0;
+		cur_pos = stpcpy(cur_pos, &rdata[1]);
+	    } else
+		cur_pos = stpcpy(cur_pos, rdata);
+	    free(rdata);
+	}
+	txts->data[i] = (uint8_t *)strdup(txt_field);
+	if (!txts->data[i])
+	{
+	    *err = TWC_DNS_RC_ERROR;
+	    goto err_resp;
+	}
+	++txts->count;
+    }
+    goto err_txt; // Normal return
+
+  err_resp:
+    resolve_response_list_deep_free(txts);
+    txts = NULL;
+  err_txt:
+    ldns_rr_list_deep_free(txt);
+  err_pkt:
+    ldns_resolver_deep_free(res);
+  err:
+    return txts;
+}
+
+static uint8_t *
+resolve_toxdns1(const t_twc_toxdns_data *data, enum t_twc_dns_rc *error)
+{
+    char buf[TWC_DNS_ID_MAXLEN + 2];
+    t_resolve_response_list *id_rrs;
+    uint8_t *toxid = NULL;
+    *error = TWC_DNS_RC_OK;
+
+    sprintf(buf, "%s.%s", data->name, data->domain);
+    id_rrs = twc_ldns_resolve(buf, error);
+    if (!id_rrs)
+	goto err;
+
+    for (size_t j = 0; j < id_rrs->count; ++j)
+    {
+	uint8_t *id_rr = resolve_response_data(id_rrs, j);
+	if (strncmp("v=tox1;id=", (char *)id_rr, 10))
+        {
+            *error = TWC_DNS_RC_VERSION;
+            continue;
+        }
+        toxid = (uint8_t *)strndup((char *)&id_rr[10], TOX_ADDRESS_SIZE * 2);
+        if (!toxid)
+        {
+            *error = TWC_DNS_RC_ERROR;
+            goto err_id;
+        }
+        *error = TWC_DNS_RC_OK;
+        break;
+    }
+
+  err_id:
+    resolve_response_list_deep_free(id_rrs);
+  err:
+    return toxid;
+}
+
 /**
  * Callback when the DNS resolver child process has written to our file
  * descriptor. Process the data a bit and pass it on to the original callback.
@@ -87,7 +398,35 @@ twc_dns_fd_callback(void *data, int fd)
 void
 twc_perform_dns_lookup(const char *dns_id, int out_fd)
 {
-    dprintf(out_fd, "%d", TWC_DNS_RC_ERROR);
+    enum t_twc_dns_rc err = TWC_DNS_RC_OK;
+    t_twc_toxdns_data *d;
+    uint8_t *toxid;
+
+    if (!dns_id || weechat_strlen_screen(dns_id) > TWC_DNS_ID_MAXLEN)
+    {
+	err = TWC_DNS_RC_EINVAL;
+	goto err;
+    }
+    /* Split name from domain in preparation for tox3dns protocol. */
+    d = split_name(dns_id, &err);
+    
+    if (!d)
+    {
+	err = TWC_DNS_RC_EINVAL;
+	goto err;
+    }
+
+    /* For now only resolve Tox DNS version 1 addresses */
+    toxid = resolve_toxdns1(d, &err);
+    if (!toxid)
+	goto err;
+
+  err:
+    if (err)
+	dprintf(out_fd, "%d", err);
+    else
+	dprintf(out_fd, "%s", toxid);
+    toxdns_data_deep_free(d);
 }
 
 /**

src/twc-dns.h

@@ -22,10 +22,19 @@
 
 #include <stdint.h>
 
+#ifdef LDNS_ENABLED
+#include <tox/toxdns.h>
+
+#define TWC_DNS_ID_MAXLEN TOXDNS_MAX_RECOMMENDED_NAME_LENGTH
+
+#endif // LDNS_ENABLED
+
 enum t_twc_dns_rc
 {
     TWC_DNS_RC_OK = 0,
     TWC_DNS_RC_ERROR = -1,
+    TWC_DNS_RC_EINVAL = -2,
+    TWC_DNS_RC_VERSION = -4,
 };
 
 enum t_twc_dns_rc