From 76e6067e13831569deca05dbb557d921998e3eb2 Mon Sep 17 00:00:00 2001
From: David Härdeman <david@hardeman.nu>
Date: Thu, 11 Jun 2020 23:08:45 +0200
Subject: Create a helper function to loop through different possible
 connections and convert proxy to use it

---
 utils.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 93 insertions(+), 1 deletion(-)

(limited to 'utils.c')

diff --git a/utils.c b/utils.c
index 0718ea9..8749c75 100644
--- a/utils.c
+++ b/utils.c
@@ -164,7 +164,7 @@ debug_resource_usage()
 }
 
 void
-socket_set_gaming_options(struct cfg *cfg, int sfd)
+socket_set_low_latency(struct cfg *cfg, int sfd)
 {
 	int option;
 
@@ -187,6 +187,98 @@ socket_set_gaming_options(struct cfg *cfg, int sfd)
 		perror("setsockopt");
 }
 
+static void
+connection_set_local_addr(struct cfg *cfg, struct connection *conn, int fd)
+{
+	if (fd < 0 || getsockname(fd, (struct sockaddr *)&conn->local.storage,
+				  &conn->local.addrlen) < 0)
+		sprintf(conn->localstr, "<unknown>");
+	else
+		sockaddr_to_str(&conn->local, conn->localstr, sizeof(conn->localstr));
+}
+
+static void connect_next(struct cfg *cfg, struct uring_task *task, struct connection *conn);
+
+static void
+connect_cb(struct cfg *cfg, struct uring_task *task, int res)
+{
+	struct connection *conn = task->priv;
+
+	if (res < 0) {
+		fprintf(stderr, "%s: connection to %s failed\n",
+			__func__, conn->remotestr);
+		uring_task_close_fd(cfg, task);
+		connect_next(cfg, task, conn);
+		return;
+	}
+
+	connection_set_local_addr(cfg, conn, task->fd);
+
+	fprintf(stderr, "%s: (%s) connection established %s -> %s\n",
+		__func__, task->name, conn->localstr, conn->remotestr);
+
+	conn->callback(cfg, conn, true);
+}
+
+static void
+connect_next(struct cfg *cfg, struct uring_task *task, struct connection *conn)
+{
+        struct sockaddr_in46 *remote, *tmp;
+        int sfd;
+        unsigned i;
+
+again:
+	i = 0;
+        remote = NULL;
+        list_for_each_entry(tmp, conn->addrs, list) {
+                if (i == conn->next_addr) {
+                        remote = tmp;
+                        break;
+                }
+                i++;
+        }
+
+        if (!remote) {
+                fprintf(stderr, "%s: no more remote addresses to attempt\n", __func__);
+		conn->callback(cfg, conn, false);
+                return;
+        }
+
+	conn->next_addr++;
+        conn->remote = *remote;
+	sockaddr_to_str(&conn->remote, conn->remotestr, sizeof(conn->remotestr));
+        fprintf(stderr, "%s: attempting to connect to %s\n",
+		task->name, conn->remotestr);
+
+        sfd = socket(conn->remote.storage.ss_family, SOCK_STREAM | SOCK_CLOEXEC, 0);
+        if (sfd < 0) {
+                perror("socket");
+                goto again;
+        }
+
+	socket_set_low_latency(cfg, sfd);
+
+	task->priv = conn;
+        uring_task_set_fd(task, sfd);
+        uring_connect(cfg, task, &conn->remote, connect_cb);
+}
+
+void
+connect_any(struct cfg *cfg, struct uring_task *task,
+	    struct list_head *addrs, struct connection *conn,
+	    void (*callback)(struct cfg *, struct connection *, int res))
+{
+	if (!cfg || !task || !addrs || !conn || !callback) {
+		fprintf(stderr, "%s: invalid arguments\n", __func__);
+		return;
+	}
+
+	conn->next_addr = 0;
+	conn->addrs = addrs;
+	conn->callback = callback;
+	connect_next(cfg, task, conn);
+}
+
 uint16_t sockaddr_port(struct sockaddr_in46 *addr)
 {
 	switch (addr->storage.ss_family) {
-- 
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