From 3ceee41d33d4ce6547df164ba84cd3369405306b Mon Sep 17 00:00:00 2001
From: Davide Beatrici <davidebeatrici@gmail.com>
Date: Fri, 20 Apr 2018 17:33:07 +0200
Subject: [PATCH] OpenVPN: hostname support

OpenVPN sends the default gateway's MAC address, if the option --push-peer-info is enabled.
It also sends the client's environment variables whose names start with "UV_".

This commit adds some lines of code in OvsBeginIPCAsyncConnectionIfEmpty(), in order to set the hostname to "UV_HOSTNAME"'s value, which is defined by the user on their device.
In case "UV_HOSTNAME" is not available, "IV_HWADDR"'s value (the default gateway's MAC address) is used instead.

OvsParseOptions() has been adapted into a new function called OvsParsePeerInfo(), in order to parse the peer info string.
---
 src/Cedar/Interop_OpenVPN.c | 54 +++++++++++++++++++++++++++++++++++++
 src/Cedar/Interop_OpenVPN.h |  1 +
 2 files changed, 55 insertions(+)

diff --git a/src/Cedar/Interop_OpenVPN.c b/src/Cedar/Interop_OpenVPN.c
index 366ce95f..d248259b 100644
--- a/src/Cedar/Interop_OpenVPN.c
+++ b/src/Cedar/Interop_OpenVPN.c
@@ -673,6 +673,7 @@ void OvsBeginIPCAsyncConnectionIfEmpty(OPENVPN_SERVER *s, OPENVPN_SESSION *se, O
 
 	if (se->IpcAsync == NULL)
 	{
+		LIST *pi;
 		IPC_PARAM p;
 		ETHERIP_ID id;
 
@@ -702,6 +703,24 @@ void OvsBeginIPCAsyncConnectionIfEmpty(OPENVPN_SERVER *s, OPENVPN_SESSION *se, O
 			StrCpy(p.CryptName, sizeof(p.CryptName), c->CipherEncrypt->Name);
 		}
 
+		// OpenVPN sends the default gateway's MAC address,
+		// if the option --push-peer-info is enabled.
+		// It also sends all of the client's environment
+		// variables whose names start with "UV_".
+		pi = OvsParsePeerInfo(c->ClientKey.PeerInfo);
+
+		// Check presence of custom hostname
+		if (OvsHasOption(pi, "UV_HOSTNAME"))
+		{
+			StrCpy(p.ClientHostname, sizeof(p.ClientHostname), IniStrValue(pi, "UV_HOSTNAME"));
+		}
+		else // Use the default gateway's MAC address
+		{
+			StrCpy(p.ClientHostname, sizeof(p.ClientHostname), IniStrValue(pi, "IV_HWADDR"));
+		}
+
+		OvsFreeOptions(pi);
+
 		if (se->Mode == OPENVPN_MODE_L3)
 		{
 			// L3 Mode
@@ -1000,6 +1019,41 @@ LIST *OvsParseOptions(char *str)
 	return o;
 }
 
+// Parse the peer info string
+LIST *OvsParsePeerInfo(char *str)
+{
+	LIST *o = NewListFast(NULL);
+	TOKEN_LIST *t;
+
+	t = ParseTokenWithoutNullStr(str, "\n");
+	if (t != NULL)
+	{
+		UINT i;
+
+		for (i = 0;i < t->NumTokens;i++)
+		{
+			char key[MAX_SIZE];
+			char value[MAX_SIZE];
+			char *line = t->Token[i];
+			Trim(line);
+
+			if (GetKeyAndValue(line, key, sizeof(key), value, sizeof(value), "=\t"))
+			{
+				INI_ENTRY *e = ZeroMalloc(sizeof(INI_ENTRY));
+
+				e->Key = CopyStr(key);
+				e->Value = CopyStr(value);
+
+				Add(o, e);
+			}
+		}
+
+		FreeToken(t);
+	}
+
+	return o;
+}
+
 // Release the option list
 void OvsFreeOptions(LIST *o)
 {
diff --git a/src/Cedar/Interop_OpenVPN.h b/src/Cedar/Interop_OpenVPN.h
index 4157206a..a1b3901a 100644
--- a/src/Cedar/Interop_OpenVPN.h
+++ b/src/Cedar/Interop_OpenVPN.h
@@ -362,6 +362,7 @@ BUF *OvsBuildKeyMethod2(OPENVPN_KEY_METHOD_2 *d);
 void OvsWriteStringToBuf(BUF *b, char *str, UINT max_size);
 
 LIST *OvsParseOptions(char *str);
+LIST *OvsParsePeerInfo(char *str);
 void OvsFreeOptions(LIST *o);
 LIST *OvsNewOptions();
 void OvsAddOption(LIST *o, char *key, char *value);