zsh: generalize port forwarding function

.config/zsh/functions/forward-local-port

@@ -1,23 +0,0 @@
-#!/usr/bin/env zsh
-# Forward a local port to a server via SSH tunnel.
-
-setopt LOCAL_OPTIONS ERR_RETURN NO_UNSET PIPE_FAIL
-
-zmodload zsh/zutil
-local -a o_help=()
-local -a o_lport=()
-local -a o_rport=()
-zparseopts -D -K -- h=o_help -help=o_help -local-port:=o_lport -remote-port:=o_rport
-if [[ ${#o_help} -ne 0 || ! -v 1 || ${#o_lport} -ne 2 || ${#o_rport} -ne 2 ]]; then
-    local ret=$(( ${#o_help} ^ 1 ))
-    print -u $(( 1 + ${ret} )) "usage: ${0} [-h|--help]" \
-          "--local-port <PORT> --remote-port <PORT> <HOST>"
-    return ${ret}
-fi
-local host=${1}
-local lport=${o_lport[2]}
-local rport=${o_rport[2]}
-
-print -P "%F{12}Forwarding local port%f %F{13}${lport}%f %F{12}over SSH tunnel" \
-      "to%f" "%F{13}${host}%f %F{12}port%f %F{13}${rport}%f %F{12}…%f"
-ssh -R ${rport}:"[::1]":${lport} -N -T ${host}

.config/zsh/functions/forward-port

@@ -0,0 +1,41 @@
+#!/usr/bin/env zsh
+# Forward a port to or from a server via SSH tunnel.
+
+setopt LOCAL_OPTIONS ERR_RETURN NO_UNSET PIPE_FAIL
+
+zmodload zsh/zutil
+local -a o_help=()
+local -a o_to_us=()
+local -a o_from_us=()
+local -a o_lport=()
+local -a o_rport=()
+zparseopts -D -K -- h=o_help -help=o_help -to-us=o_to_us -from-us=o_from_us \
+    -local-port:=o_lport -remote-port:=o_rport
+
+if [[ ${#o_help} -ne 0 || ! -v 1 || ${#o_lport} -ne 2 || ${#o_rport} -ne 2 ]]; then
+    local ret=$(( ${#o_help} ^ 1 ))
+    print -u $(( 1 + ${ret} )) "usage: ${0} [-h|--help]" \
+          "--local-port <PORT> --remote-port <PORT> <HOST>"
+    return ${ret}
+fi
+if [[ ${#o_to_us} -ne 2 && ${#o_from_us} -ne 2 ]]; then
+    print -u 2 "no direction given, assuming --to-us"
+fi
+
+local host=${1}
+local direction="-L" # from remote to us
+if [[ ${#o_from_us} -ne 2 ]]; then
+    direction="-R"
+fi
+local lport=${o_lport[2]}
+local rport=${o_rport[2]}
+
+if [[ ${direction} == "-L" ]]; then
+    print -P "%F{12}forwarding remote port%f %F{13}${rport}%f %F{12}over SSH tunnel" \
+        "to%f" "%F{13}${host}%f %F{12}port%f %F{13}${lport}%f %F{12}…%f"
+    ssh -L ${lport}:"[::1]":${rport} -N -T ${host}
+elif [[ ${direction} == "-R" ]]; then
+    print -P "%F{12}forwarding local port%f %F{13}${lport}%f %F{12}over SSH tunnel" \
+        "to%f" "%F{13}${host}%f %F{12}port%f %F{13}${rport}%f %F{12}…%f"
+    ssh -R ${rport}:"[::1]":${lport} -N -T ${host}
+fi