From daf57c0410b3a67a3045d407d0d65e30841d4d88 Mon Sep 17 00:00:00 2001
From: Jesse Engle <bopwerks@acm.org>
Date: Mon, 4 Sep 2023 09:16:47 -0400
Subject: [PATCH] Adds socket family and datagram functions for communicating
 via netlink protocol.

---
 cffi-socket.lisp   | 40 ++++++++++++++++++++++++++++++++++++++++
 grovel-socket.lisp | 13 +++++++------
 package.lisp       |  5 +++++
 3 files changed, 52 insertions(+), 6 deletions(-)

diff --git a/cffi-socket.lisp b/cffi-socket.lisp
index e7edf10..4aa4a77 100644
--- a/cffi-socket.lisp
+++ b/cffi-socket.lisp
@@ -206,6 +206,26 @@
           (error-errno "recv"))
         r))))
 
+(defcfun ("recvfrom" c-recvfrom) ssize-t
+  (sockfd :int)
+  (buf :pointer)
+  (len size-t)
+  (flags :int)
+  (src-addr (:pointer (:struct sockaddr)))
+  (addrlen (:pointer socklen-t)))
+
+(defun recv-from (sockfd buffer flags &key (srcaddr (null-pointer)) (addrlen (null-pointer)) (start 0) (end (length buffer)))
+  (declare (type (array (unsigned-byte 8)) buffer))
+  (let ((len (- end start)))
+    (with-foreign-pointer (buf len)
+      (let ((r (c-recvfrom sockfd buf len flags srcaddr addrlen)))
+        (dotimes (i len)
+          (setf (aref buffer start) (mem-aref buf :unsigned-char i))
+          (incf start))
+        (when (< r 0)
+          (error-errno "recv-from"))
+        r))))
+
 (defun recv-sequence (sockfd buffer flags &key (start 0) (end (length buffer)))
   (loop
      (unless (< start end)
@@ -242,6 +262,26 @@
          (error "end of file"))
        (incf start r))))
 
+(defcfun ("sendto" c-sendto) ssize-t
+  (sockfd :int)
+  (buf :pointer)
+  (len size-t)
+  (flags :int)
+  (dest-addr (:pointer (:struct sockaddr)))
+  (addrlen socklen-t))
+
+(defun send-to (sockfd buffer flags dstaddr addrlen &key (start 0) (end (length buffer)))
+  (declare (type (array (unsigned-byte 8)) buffer))
+  (let ((len (- end start)))
+    (with-foreign-pointer (buf len)
+      (let ((r (c-sendto sockfd buf len flags dstaddr addrlen)))
+        (dotimes (i len)
+          (setf (aref buffer start) (mem-aref buf :unsigned-char i))
+          (incf start))
+        (when (< r 0)
+          (error-errno "send-to"))
+        r))))
+
 (defcfun ("shutdown" c-shutdown) :int
   (sockfd :int)
   (how :int))
diff --git a/grovel-socket.lisp b/grovel-socket.lisp
index 24a7d6c..481d200 100644
--- a/grovel-socket.lisp
+++ b/grovel-socket.lisp
@@ -23,12 +23,13 @@
 (include "sys/types.h")
 (include "sys/socket.h")
 
-(constant (+af-unix+   "AF_UNIX"))
-(constant (+af-local+  "AF_LOCAL"))
-(constant (+af-inet+   "AF_INET"))
-(constant (+af-inet6+  "AF_INET6"))
-(constant (+af-ipx+    "AF_IPX"))
-(constant (+af-packet+ "AF_PACKET"))
+(constant (+af-unix+    "AF_UNIX"))
+(constant (+af-local+   "AF_LOCAL"))
+(constant (+af-inet+    "AF_INET"))
+(constant (+af-inet6+   "AF_INET6"))
+(constant (+af-ipx+     "AF_IPX"))
+(constant (+af-packet+  "AF_PACKET"))
+(constant (+af-netlink+ "AF_NETLINK"))
 
 (constant (+sock-stream+ "SOCK_STREAM"))
 (constant (+sock-dgram+  "SOCK_DGRAM"))
diff --git a/package.lisp b/package.lisp
index 83a74b5..c6bad92 100644
--- a/package.lisp
+++ b/package.lisp
@@ -33,6 +33,7 @@
    #:+af-local+
    #:+af-packet+
    #:+af-unix+
+   #:+af-netlink+
    #:+shut-rd+
    #:+shut-rdwr+
    #:+shut-wr+
@@ -51,7 +52,9 @@
    #:c-listen
    #:c-ntohs
    #:c-recv
+   #:c-recvfrom
    #:c-send
+   #:c-sendto
    #:c-shutdown
    #:c-socket
    #:connect
@@ -62,8 +65,10 @@
    #:listen
    #:ntohs
    #:recv
+   #:recv-from
    #:recv-sequence
    #:send
+   #:send-to
    #:send-sequence
    #:shutdown
    #:sockaddr-to-string