From 20451db88cdc9d91454e3747f37777ae805d3fda Mon Sep 17 00:00:00 2001
From: "Else, Someone" <else@someonex.net>
Date: Fri, 7 Nov 2025 19:04:58 +0200
Subject: [PATCH] ch-proxy: support normal vsock

---
 pkgs/ch-proxy/proxy.c | 89 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 81 insertions(+), 8 deletions(-)

diff --git a/pkgs/ch-proxy/proxy.c b/pkgs/ch-proxy/proxy.c
index 78bfefd..ed1dea0 100644
--- a/pkgs/ch-proxy/proxy.c
+++ b/pkgs/ch-proxy/proxy.c
@@ -7,6 +7,8 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 
+#include <linux/vm_sockets.h>
+
 struct msghdr mk_msghdr();
 int ch_connect(const char*, const char*);
 ssize_t send_fd(int, int);
@@ -18,7 +20,8 @@ void print_usage() {
             "Usage:\n"
             "\tch-proxy uvm/$USER_VM_NAME [PORT]\n"
             "\tch-proxy uuvm/$VM_NAME [PORT]\n"
-            "\tch-proxy vsock-mux%$PATH [PORT]\n");
+            "\tch-proxy vsock-mux%$PATH [PORT]\n"
+            "\tch-proxy vsock/cid[:port]\n");
 }
 
 char *extract_vsock_mux(const char *host_string) {
@@ -67,6 +70,50 @@ char *extract_muvm(const char *host_string) {
     return result;
 }
 
+int extract_cid(const char *host, int *cid, int *port) {
+    if (errno != 0) {
+        perror("extract_cid(...): errno unclean");
+        exit(EXIT_FAILURE);
+    }
+
+    const char PREFIX[] = "vsock/";
+    const ssize_t PREFIX_LEN = sizeof(PREFIX) - 1;
+
+    if (strncmp(host, PREFIX, PREFIX_LEN) != 0) {
+        return 1;
+    }
+
+    char *in = NULL;
+    const char *end = host + strlen(host);
+    const char *sCid = host + PREFIX_LEN;
+
+    long x;
+    x = strtol(sCid, &in, 10);
+    if (errno != 0) {
+        perror("strtol(cid, ...)");
+        exit(EXIT_FAILURE);
+    }
+    *cid = (int) x;
+
+    if (in == end) {
+        *port = 22;
+        return 0;
+    } else if (in[0] != ':') {
+        perror("extract_cid(...): expected a string of the form cid[:port]");
+        perror(host);
+        exit(EXIT_FAILURE);
+    }
+
+    const char *sPort = in + 1;
+    x = strtol(sPort, &in, 10);
+    if (errno != 0) {
+        perror("strtol(port, ...)");
+        exit(EXIT_FAILURE);
+    }
+    *port = (int) x;
+    return 0;
+}
+
 int main(int argc, char** argv) {
     if (!(2 <= argc && argc <= 3)) {
         fprintf(stderr, "%s: Wrong # of arguments: %d\n", argv[0], argc);
@@ -79,21 +126,47 @@ int main(int argc, char** argv) {
     const char *ssh_host = argv[1];
     const char *port_string = argc == 3 ? argv[2] : PORT_DEFAULT;
 
-    char *path_un;
+    int cid = -1, port = -1;
+    char *path_un = NULL;
     if ((path_un = extract_uvm(ssh_host)) != NULL) {
     } else if ((path_un = extract_muvm(ssh_host)) != NULL) {
     } else if ((path_un = extract_vsock_mux(ssh_host)) != NULL) {
+    } else if (extract_cid(ssh_host, &cid, &port) == 0) {
     } else {
-        fprintf(stderr, "ch-proxy/main: unexpected host stirng format: %s\n", ssh_host);
+        fprintf(stderr, "ch-proxy/main: unexpected host string format: %s\n", ssh_host);
         print_usage();
         return EXIT_FAILURE;
     }
 
-    const int s = ch_connect(path_un, port_string);
-    if (s == -1) {
-        perror("ssh-vsock-proxy/main/ch_connect");
-        return EXIT_FAILURE;
-    };
+    int s = -1;
+
+    if (path_un != NULL)  {
+        s = ch_connect(path_un, port_string);
+        if (s == -1) {
+            perror("ssh-vsock-proxy/main/ch_connect");
+            return EXIT_FAILURE;
+        };
+    } else if (cid != -1 && port != -1) {
+        struct sockaddr_vm sa = {
+            .svm_family = AF_VSOCK,
+            .svm_reserved1 = 0,
+            .svm_port = port,
+            .svm_cid = cid,
+        };
+        memset(sa.svm_zero, 0, sizeof(sa.svm_zero));
+        s = socket(AF_VSOCK, SOCK_STREAM, 0);
+        if (s == -1) {
+            perror("socket(AF_VSOCK, ...)");
+            exit(EXIT_FAILURE);
+        }
+        if (connect(s, (struct sockaddr*)&sa, sizeof(sa)) != 0) {
+            perror("connect(socket(AF_VSOCK, ...), ...)");
+            exit(EXIT_FAILURE);
+        }
+    } else {
+        perror("Couldn't parse neither uuvm/ strings nor vsock/cid[:port]");
+        exit(EXIT_FAILURE);
+    }
 
     if (send_fd(1, s) == -1) {
         perror("ssh-vsock-proxy/main/send_fd");