update stuffs

shared.h

@@ -0,0 +1,120 @@
+#pragma once
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+
+#define CC_ADDRLEN (INET6_ADDRSTRLEN + 8) // [...:12345]
+
+static int sockaddr2str(const struct sockaddr *sa, char *s, const size_t maxlen) {
+    if (sa->sa_family == AF_INET) {
+        const struct sockaddr_in *sin = (struct sockaddr_in *)sa;
+        inet_ntop(AF_INET, &sin->sin_addr, s, maxlen);
+        const size_t len = strnlen(s, maxlen);
+        return len + snprintf(s + len, maxlen - len, ":%u", ntohs(sin->sin_port));
+    }
+
+    if (sa->sa_family == AF_INET6) {
+        const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
+        s[0] = '[';
+        inet_ntop(AF_INET6, &sin6->sin6_addr, s + 1, maxlen - 1);
+        const size_t len = strnlen(s, maxlen);
+        return len + snprintf(s + len, maxlen - len, "]:%u", ntohs(sin6->sin6_port));
+    }
+
+    strncpy(s, "unknown", maxlen);
+    return 7;
+}
+
+#define MAX_MESSAGE_LENGTH 1024
+
+#define streq(a, b) (strcmp((a), (b)) == 0)
+
+#define exit_error(...) do { \
+    fprintf(stderr, __VA_ARGS__); \
+    exit(EXIT_FAILURE); \
+} while (0)
+
+#define exit_perror(s) do { \
+    perror(s); \
+    exit(EXIT_FAILURE); \
+} while (0)
+
+static int resolve_domain_to_ipv6(const char *hostname, struct in6_addr *server_addr) {
+    struct addrinfo hints, *res;
+    int found = 0;
+
+    memset(&hints, 0, sizeof hints);
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_socktype = SOCK_STREAM;
+
+    if (getaddrinfo(hostname, NULL, &hints, &res) != 0) return 0;
+
+    for (struct addrinfo *p = res; p != NULL; p = p->ai_next) {
+        if (p->ai_family == AF_INET6) {
+            struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)p->ai_addr;
+            memcpy(server_addr, &ipv6->sin6_addr, sizeof(struct in6_addr));
+            found = 1;
+            break;
+        }
+        if (p->ai_family == AF_INET && !found) {
+            struct sockaddr_in *ipv4 = (struct sockaddr_in *)p->ai_addr;
+            memset(server_addr, 0, sizeof(struct in6_addr));
+            server_addr->s6_addr[10] = 0xff;
+            server_addr->s6_addr[11] = 0xff;
+            memcpy(&server_addr->s6_addr[12], &(ipv4->sin_addr), 4);
+            found = 1;
+        }
+    }
+
+    freeaddrinfo(res);
+    return found;
+}
+
+static int cc_client_parse_args_and_connect(int argc, char* argv[], struct sockaddr_in6* server_addr, int* server_fd, FILE** reader, FILE** writer) {
+    struct in6_addr bind_addr = in6addr_any;
+    int port = 5000;
+    if (argc >= 2) {
+        if (inet_pton(AF_INET6, argv[1], &bind_addr) != 1) {
+            struct in_addr v4;
+            if (inet_pton(AF_INET, argv[1], &v4) != 1) {
+                if (!resolve_domain_to_ipv6(argv[1], &bind_addr)) {
+                    exit_error("invalid address or domain: %s\n", argv[1]);
+                }
+            }
+            else {
+                memset(&bind_addr, 0, sizeof(bind_addr));
+                bind_addr.s6_addr[10] = 0xff;
+                bind_addr.s6_addr[11] = 0xff;
+                memcpy(&bind_addr.s6_addr[12], &v4, 4);
+            }
+        }
+    }
+    if (argc >= 3) {
+        port = atoi(argv[2]);
+        if (port <= 0) exit_error("unknown argument: %s\n", argv[2]);
+    }
+
+    *server_fd = socket(AF_INET6, SOCK_STREAM, 0);
+    if (*server_fd < 0) exit_perror("socket");
+    const int server_fd2 = dup(*server_fd);
+    if (server_fd2 < 0) exit_perror("dup");
+
+    server_addr->sin6_family = AF_INET6;
+    server_addr->sin6_addr = bind_addr;
+    server_addr->sin6_port = htons(port);
+
+    int opt = 0;
+    if (setsockopt(*server_fd, IPPROTO_IPV6, IPV6_V6ONLY, &opt, sizeof(opt)) < 0) {
+        // i guess so bro
+    }
+
+    if (connect(*server_fd, (struct sockaddr *)server_addr, sizeof(*server_addr)) < 0) exit_perror("connect");
+
+    if ((*reader = fdopen(*server_fd,  "r")) == NULL) exit_perror("fdopen reader");
+    if ((*writer = fdopen(server_fd2, "w")) == NULL) exit_perror("fdopen writer");
+    return 0;
+}