From 379943e12ea96f9133f3765e5c36c3405babada2 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
Date: Fri, 1 Jan 2021 16:38:03 +0100
Subject: [PATCH] pppoe: Dump discovery packets when pppoe-verbose option is
 set to >= 2
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Signed-off-by: Pali Rohár <pali@kernel.org>
---
 pppd/plugins/pppoe/common.c | 38 +++++++++++++++++++++++++++++++++++++
 pppd/pppd.8                 |  5 +++--
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/pppd/plugins/pppoe/common.c b/pppd/plugins/pppoe/common.c
index 9ea7fd6..9140ea9 100644
--- a/pppd/plugins/pppoe/common.c
+++ b/pppd/plugins/pppoe/common.c
@@ -160,6 +160,42 @@ sendPADT(PPPoEConnection *conn, char const *msg)
     info("Sent PADT");
 }
 
+static void
+pppoe_printpkt_hex(void (*printer)(void *, char *, ...), void *arg, unsigned char const *buf, int len)
+{
+    int i;
+    int base;
+
+    /* do NOT dump PAP packets */
+    if (len >= 2 && buf[0] == 0xC0 && buf[1] == 0x23) {
+	printer(arg, "(PAP Authentication Frame -- Contents not dumped)\n");
+	return;
+    }
+
+    for (base=0; base<len; base += 16) {
+	for (i=base; i<base+16; i++) {
+	    if (i < len) {
+		printer(arg, "%02x ", (unsigned) buf[i]);
+	    } else {
+		printer(arg, "   ");
+	    }
+	}
+	printer(arg, "  ");
+	for (i=base; i<base+16; i++) {
+	    if (i < len) {
+		if (isprint(buf[i])) {
+		    printer(arg, "%c", buf[i]);
+		} else {
+		    printer(arg, ".");
+		}
+	    } else {
+		break;
+	    }
+	}
+	printer(arg, "\n");
+    }
+}
+
 #define EH(x)	(x)[0], (x)[1], (x)[2], (x)[3], (x)[4], (x)[5]
 
 /* Print out a PPPOE packet for debugging */
@@ -207,6 +243,8 @@ void pppoe_printpkt(PPPoEPacket *packet,
 
     printer(arg, " dst %02x:%02x:%02x:%02x:%02x:%02x ", EH(packet->ethHdr.h_dest));
     printer(arg, " src %02x:%02x:%02x:%02x:%02x:%02x\n", EH(packet->ethHdr.h_source));
+    if (pppoe_verbose >= 2)
+	pppoe_printpkt_hex(printer, arg, packet->payload, ntohs(packet->length));
     if (ntohs(packet->ethHdr.h_proto) != ETH_PPPOE_DISCOVERY)
 	return;
 
diff --git a/pppd/pppd.8 b/pppd/pppd.8
index 36156d6..cbbcb45 100644
--- a/pppd/pppd.8
+++ b/pppd/pppd.8
@@ -1243,8 +1243,9 @@ Attach to existing PPPoE session. For backward compatibility also
 \fBrp_pppoe_sess\fP option name is supported.
 .TP
 .B pppoe-verbose \fIn
-Be verbose about discovered access concentrators. For backward
-compatibility also \fBrp_pppoe_verbose\fP option name is supported.
+Be verbose about discovered access concentrators. When set to 2 or bigger
+value then dump also discovery packets. For backward compatibility also
+\fBrp_pppoe_verbose\fP option name is supported.
 .TP
 .B pppoe-mac \fImacaddr
 Connect to specified MAC address.
-- 
2.39.2