From 79ff87bd02d21379c33496c1fa50a89312773140 Mon Sep 17 00:00:00 2001
From: Beniamin Sandu <beniaminsandu@gmail.com>
Date: Fri, 23 Sep 2022 14:10:07 +0200
Subject: libnet_raw: don't change the TX buffer size for raw sockets

Instead of trying to set the max TX buffer size for every raw
socket, export this to a separate interface that can be used
when needed, called libnet_setfd_max_sndbuf().

Signed-off-by: Beniamin Sandu <beniaminsandu@gmail.com>
---
 ChangeLog.md                      |  3 +++
 include/libnet/libnet-functions.h | 12 ++++++++++++
 src/libnet_init.c                 | 20 ++++++++++++++++++++
 src/libnet_raw.c                  | 37 -------------------------------------
 4 files changed, 35 insertions(+), 37 deletions(-)

diff --git a/ChangeLog.md b/ChangeLog.md
index 7a9d7fd..cfe649e 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -10,6 +10,9 @@ of contributors, see the GIT commit log.
 
 ### Changes
 
+- Don't try to configure TX buffer max size for every raw socket. Instead, add a new API
+  that can be used when needed, called `libnet_setfd_max_sndbuf()`.
+
 ### Fixes
 
 
diff --git a/include/libnet/libnet-functions.h b/include/libnet/libnet-functions.h
index a4e00f5..45e3656 100644
--- a/include/libnet/libnet-functions.h
+++ b/include/libnet/libnet-functions.h
@@ -101,6 +101,18 @@ LIBNET_API
 int 
 libnet_getfd(libnet_t *l);
 
+#ifdef SO_SNDBUF
+/**
+ * Tries to set the TX buffer size to a max_bytes value
+ * @param l pointer to a libnet context
+ * @param max_bytes new TX buffer size
+ * @return 0 on success, -1 on failure
+ */
+LIBNET_API
+int 
+libnet_setfd_max_sndbuf(libnet_t *l, int max_bytes);
+#endif /* SO_SNDBUF */
+
 /**
  * Returns the canonical name of the device used for packet injection.
  * @param l pointer to a libnet context
diff --git a/src/libnet_init.c b/src/libnet_init.c
index fe5b613..5350aab 100644
--- a/src/libnet_init.c
+++ b/src/libnet_init.c
@@ -172,6 +172,26 @@ libnet_getfd(libnet_t *l)
     return (int)(l->fd);
 }
 
+#ifdef SO_SNDBUF
+int
+libnet_setfd_max_sndbuf(libnet_t *l, int max_bytes)
+{
+    if (l == NULL)
+        return (-1);
+
+    /* Try to set the buffer size to max_bytes */
+    if (setsockopt(l->fd, SOL_SOCKET, SO_SNDBUF, &max_bytes, sizeof(max_bytes)) < 0)
+    {
+        snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
+                    "%s(): set SO_SNDBUF failed: %s",
+                    __func__, strerror(errno));
+        return (-1);
+    }
+
+    return (0);
+}
+#endif /* SO_SNDBUF */
+
 const char *
 libnet_getdevice(libnet_t *l)
 {
diff --git a/src/libnet_raw.c b/src/libnet_raw.c
index 5195b75..f74d7b0 100644
--- a/src/libnet_raw.c
+++ b/src/libnet_raw.c
@@ -79,40 +79,6 @@ static int libnet_finish_setup_socket(libnet_t *l)
 #endif
     unsigned len;
 
-#ifdef SO_SNDBUF
-
-/*
- * man 7 socket 
- *
- * Sets and  gets  the  maximum  socket  send buffer in bytes. 
- *
- * Taken from libdnet by Dug Song
- */
-    len = sizeof(n);
-    if (getsockopt(l->fd, SOL_SOCKET, SO_SNDBUF, &n, &len) < 0)
-    {
-        snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
-		 "%s(): get SO_SNDBUF failed: %s",
-		 __func__, strerror(errno));
-        goto bad;
-    }
-    
-    for (n += 128; n < 1048576; n += 128)
-    {
-        if (setsockopt(l->fd, SOL_SOCKET, SO_SNDBUF, &n, len) < 0)
-        {
-            if (errno == ENOBUFS)
-            {
-                break;
-            }
-             snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
-                     "%s(): set SO_SNDBUF failed: %s",
-                     __func__, strerror(errno));
-             goto bad;
-        }
-    }
-#endif
-
 #ifdef SO_BROADCAST
 /*
  * man 7 socket
@@ -146,9 +112,6 @@ bad:
     return (-1);
 }
 
-
-
-
 int
 libnet_open_raw4(libnet_t *l)
 {
-- 
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