openalias: initial commit

Initial commit.

2 files changed, 272 insertions, 0 deletions

diff --git a/openalias.c b/openalias.c
new file mode 100644
index 0000000..4ed1c40
--- /dev/null
+++ b/openalias.c
@@ -0,0 +1,242 @@
+#define _CRT_SECURE_NO_WARNINGS
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+#ifdef _WIN32
+#include <windows.h>
+#include <windns.h>
+#pragma comment(lib, "dnsapi.lib")
+#else
+#include <resolv.h>
+#include <arpa/nameser.h>
+#include <netinet/in.h>
+#include <errno.h>
+#include <strings.h>
+#endif
+
+#define MAX_RECORDS      16
+#define STR_MAX          256
+#define STR_TICKER_MAX    8
+#define FQDN_MAX        253
+#define LABEL_MAX        63
+#define DNS_BUF_SIZE   8192
+#define VERSION       "1.0"
+
+typedef struct {
+    char currency[STR_TICKER_MAX];
+    char address[STR_MAX];
+} openalias_record;
+
+#ifdef _WIN32
+#define str_icmp  _stricmp
+#define str_nicmp _strnicmp
+#else
+#define str_icmp  strcasecmp
+#define str_nicmp strncasecmp
+#endif
+
+static void normalize_input(char* s) {
+    for (; *s; ++s)
+        if (*s == '@')
+            *s = '.';
+}
+
+static void normalize_ticker(char* s) {
+    for (; *s; ++s)
+        *s = (char)toupper((unsigned char)*s);
+}
+
+static int is_valid_label(const char* s, size_t len) {
+    if (len == 0 || len > LABEL_MAX) return 0;
+    if (s[0] == '-' || s[len - 1] == '-') return 0;
+    for (size_t i = 0; i < len; i++) {
+        if (!(isalnum((unsigned char)s[i]) || s[i] == '-'))
+            return 0;
+    }
+    return 1;
+}
+
+static int is_valid_fqdn(const char* s) {
+    size_t len = strlen(s);
+    if (len < 3 || len > FQDN_MAX) return 0;
+
+    const char* label = s;
+    const char* p = s;
+    while (1) {
+        if (*p == '.' || *p == '\0') {
+            if (!is_valid_label(label, (size_t)(p - label)))
+                return 0;
+            if (*p == '\0') break;
+            label = p + 1;
+        }
+        p++;
+    }
+    return 1;
+}
+
+static int starts_with(const char* s, const char* prefix) {
+    return str_nicmp(s, prefix, strlen(prefix)) == 0;
+}
+
+
+static int parse_openalias(const char* txt,
+    openalias_record* rec,
+    const char* filter) {
+
+    if (!txt || !rec || !starts_with(txt, "oa1:")) return 0;
+
+    const char* p = txt + 4;
+    char currency[STR_TICKER_MAX] = { 0 };
+    size_t i = 0;
+
+    while (*p && !isspace((unsigned char)*p) && *p != ';' && i < STR_TICKER_MAX - 1)
+        currency[i++] = (char)toupper((unsigned char)*p++);
+    currency[i] = '\0';
+
+    if (currency[0] == '\0') return 0;
+    if (filter && str_icmp(filter, currency) != 0) return 0;
+
+    const char* addr = strstr(txt, "recipient_address=");
+    if (!addr) return 0;
+
+    addr += strlen("recipient_address=");
+    i = 0;
+    while (*addr && *addr != ';' && !isspace((unsigned char)*addr) && i < STR_MAX - 1)
+        rec->address[i++] = *addr++;
+    rec->address[i] = '\0';
+
+    if (rec->address[0] == '\0') return 0;
+
+    strncpy(rec->currency, currency, STR_TICKER_MAX - 1);
+    rec->currency[STR_TICKER_MAX - 1] = '\0';
+    return 1;
+}
+
+int main(int argc, char** argv) {
+
+    if (argc < 2) {
+        fprintf(stderr, "openalias address lookup v%s\n", VERSION);
+        fprintf(stderr, "usage: %s <domain> [-t ticker] (default=xmr)\n", argv[0]);
+        return EXIT_FAILURE;
+    }
+
+    if (strlen(argv[1]) > FQDN_MAX) {
+        fprintf(stderr, "error: domain name too long\n");
+        return EXIT_FAILURE;
+    }
+
+    char fqdn[FQDN_MAX + 1] = { 0 };
+    strncpy(fqdn, argv[1], FQDN_MAX);
+    fqdn[FQDN_MAX] = '\0';
+    normalize_input(fqdn);
+
+    if (!is_valid_fqdn(fqdn)) {
+        fprintf(stderr, "error: invalid fqdn\n");
+        return EXIT_FAILURE;
+    }
+
+    char filter_buf[STR_TICKER_MAX] = "XMR";
+    const char* filter = filter_buf;
+
+    if (argc == 4 && strcmp(argv[2], "-t") == 0) {
+        if (strlen(argv[3]) >= STR_TICKER_MAX) {
+            fprintf(stderr, "error: ticker too long\n");
+            return EXIT_FAILURE;
+        }
+        strncpy(filter_buf, argv[3], STR_TICKER_MAX - 1);
+        filter_buf[STR_TICKER_MAX - 1] = '\0';
+        normalize_ticker(filter_buf);
+    }
+
+    openalias_record results[MAX_RECORDS] = { 0 };
+    size_t count = 0;
+
+#ifdef _WIN32
+    DNS_RECORDA* records = NULL;
+    DNS_STATUS status = DnsQuery_A(
+        fqdn,
+        DNS_TYPE_TEXT,
+        DNS_QUERY_STANDARD,
+        NULL,
+        (PDNS_RECORD*) & records,
+        NULL
+    );
+
+    if (status != ERROR_SUCCESS) {
+        fprintf(stderr, "error: dns txt lookup failed (status %lu)\n", status);
+        return EXIT_FAILURE;
+    }
+
+    for (DNS_RECORDA* r = records; r && count < MAX_RECORDS; r = r->pNext) {
+        if (r->wType != DNS_TYPE_TEXT) continue;
+
+        char txt[STR_MAX] = { 0 };
+        size_t pos = 0;
+
+        for (DWORD i = 0; i < r->Data.TXT.dwStringCount; i++) {
+            const char* seg = r->Data.TXT.pStringArray[i];
+            size_t seglen = strlen(seg);
+            if (pos + seglen >= STR_MAX) break;
+            memcpy(txt + pos, seg, seglen);
+            pos += seglen;
+        }
+        txt[pos] = '\0';
+
+        if (parse_openalias(txt, &results[count], filter))
+            count++;
+    }
+
+    DnsRecordListFree(records, DnsFreeRecordList);
+
+#else
+    unsigned char answer[DNS_BUF_SIZE];
+    int len = res_query(fqdn, ns_c_in, ns_t_txt, answer, sizeof(answer));
+    if (len < 0) {
+        fprintf(stderr, "error: dns txt lookup failed (errno %d)\n", errno);
+        return EXIT_FAILURE;
+    }
+
+    ns_msg msg;
+    if (ns_initparse(answer, len, &msg) < 0) {
+        fprintf(stderr, "error: dns parse failed\n");
+        return EXIT_FAILURE;
+    }
+
+    int rr_count = ns_msg_count(msg, ns_s_an);
+    for (int i = 0; i < rr_count && count < MAX_RECORDS; i++) {
+        ns_rr rr;
+        if (ns_parserr(&msg, ns_s_an, i, &rr) != 0) continue;
+        if (ns_rr_type(rr) != ns_t_txt) continue;
+
+        const unsigned char* rdata = ns_rr_rdata(rr);
+        int rdlen = ns_rr_rdlen(rr);
+        char txt[STR_MAX] = { 0 };
+        size_t pos = 0;
+
+        for (int off = 0; off < rdlen;) {
+            int seglen = rdata[off++];
+            if (seglen <= 0 || off + seglen > rdlen || pos + seglen >= STR_MAX) break;
+            memcpy(txt + pos, rdata + off, seglen);
+            pos += seglen;
+            off += seglen;
+        }
+        txt[pos] = '\0';
+
+        if (parse_openalias(txt, &results[count], filter))
+            count++;
+    }
+#endif
+
+    if (count == 0) {
+        fprintf(stderr, "error: no openalias records found for %s\n", filter);
+        return EXIT_FAILURE;
+    }
+
+    for (size_t i = 0; i < count; i++)
+        puts(results[i].address);
+
+    return EXIT_SUCCESS;
+}
+
diff --git a/premake5.lua b/premake5.lua
new file mode 100644
index 0000000..2f7fbdc
--- /dev/null
+++ b/premake5.lua
@@ -0,0 +1,30 @@
+-- premake5.lua
+workspace "openalias"
+   architecture "x64"
+   configurations { "Debug", "Release" }
+   startproject "openalias"
+
+project "openalias"
+   kind "ConsoleApp"
+   language "C"
+   targetdir "bin/%{cfg.buildcfg}"
+
+   files { "openalias.c" }
+
+   filter "system:windows"
+      defines {"_WIN32" }
+      links { "dnsapi" }
+      systemversion "latest"
+
+   filter "system:linux"
+      defines { "_POSIX_C_SOURCE=200112L" }
+      links { "resolv" }
+      buildoptions { "-Wall", "-Wextra" }
+
+   filter "configurations:Debug"
+      defines { "DEBUG" }
+      symbols "On"
+
+   filter "configurations:Release"
+      defines { "NDEBUG" }
+      optimize "On"