From: Pali Rohár <pali@kernel.org>
Date: Fri, 1 Jan 2021 15:30:19 +0000 (+0100)
Subject: pppoe: Do not use lcp_allowoptions[] and lcp_wantoptions[] in discovery.c code
X-Git-Tag: ppp-2.5.0~50^2~6
X-Git-Url: https://git.ozlabs.org/?p=ppp.git;a=commitdiff_plain;h=af622602ca55d368c03b0ea912479dc84ad543c0

pppoe: Do not use lcp_allowoptions[] and lcp_wantoptions[] in discovery.c code

Signed-off-by: Pali Rohár <pali@kernel.org>
---

diff --git a/pppd/plugins/pppoe/discovery.c b/pppd/plugins/pppoe/discovery.c
index 1c55b36..1d3d12b 100644
--- a/pppd/plugins/pppoe/discovery.c
+++ b/pppd/plugins/pppoe/discovery.c
@@ -168,10 +168,10 @@ parsePADOTags(UINT16_t type, UINT16_t len, unsigned char *data,
 	    memcpy(&mru, data, sizeof(mru));
 	    mru = ntohs(mru);
 	    if (mru >= ETH_PPPOE_MTU) {
-		if (lcp_allowoptions[0].mru > mru)
-		    lcp_allowoptions[0].mru = mru;
-		if (lcp_wantoptions[0].mru > mru)
-		    lcp_wantoptions[0].mru = mru;
+		if (conn->mtu > mru)
+		    conn->mtu = mru;
+		if (conn->mru > mru)
+		    conn->mru = mru;
 		conn->seenMaxPayload = 1;
 	    }
 	}
@@ -218,10 +218,10 @@ parsePADSTags(UINT16_t type, UINT16_t len, unsigned char *data,
 	    memcpy(&mru, data, sizeof(mru));
 	    mru = ntohs(mru);
 	    if (mru >= ETH_PPPOE_MTU) {
-		if (lcp_allowoptions[0].mru > mru)
-		    lcp_allowoptions[0].mru = mru;
-		if (lcp_wantoptions[0].mru > mru)
-		    lcp_wantoptions[0].mru = mru;
+		if (conn->mtu > mru)
+		    conn->mtu = mru;
+		if (conn->mru > mru)
+		    conn->mru = mru;
 		conn->seenMaxPayload = 1;
 	    }
 	}
@@ -306,9 +306,9 @@ sendPADI(PPPoEConnection *conn)
     }
 
     /* Add our maximum MTU/MRU */
-    if (MIN(lcp_allowoptions[0].mru, lcp_wantoptions[0].mru) > ETH_PPPOE_MTU) {
+    if (MIN(conn->mtu, conn->mru) > ETH_PPPOE_MTU) {
 	PPPoETag maxPayload;
-	UINT16_t mru = htons(MIN(lcp_allowoptions[0].mru, lcp_wantoptions[0].mru));
+	UINT16_t mru = htons(MIN(conn->mtu, conn->mru));
 	maxPayload.type = htons(TAG_PPP_MAX_PAYLOAD);
 	maxPayload.length = htons(sizeof(mru));
 	memcpy(maxPayload.payload, &mru, sizeof(mru));
@@ -479,9 +479,9 @@ sendPADR(PPPoEConnection *conn)
     }
 
     /* Add our maximum MTU/MRU */
-    if (MIN(lcp_allowoptions[0].mru, lcp_wantoptions[0].mru) > ETH_PPPOE_MTU) {
+    if (MIN(conn->mtu, conn->mru) > ETH_PPPOE_MTU) {
 	PPPoETag maxPayload;
-	UINT16_t mru = htons(MIN(lcp_allowoptions[0].mru, lcp_wantoptions[0].mru));
+	UINT16_t mru = htons(MIN(conn->mtu, conn->mru));
 	maxPayload.type = htons(TAG_PPP_MAX_PAYLOAD);
 	maxPayload.length = htons(sizeof(mru));
 	memcpy(maxPayload.payload, &mru, sizeof(mru));
@@ -666,10 +666,10 @@ discovery2(PPPoEConnection *conn)
 
     if (!conn->seenMaxPayload) {
 	/* RFC 4638: MUST limit MTU/MRU to 1492 */
-	if (lcp_allowoptions[0].mru > ETH_PPPOE_MTU)
-	    lcp_allowoptions[0].mru = ETH_PPPOE_MTU;
-	if (lcp_wantoptions[0].mru > ETH_PPPOE_MTU)
-	    lcp_wantoptions[0].mru = ETH_PPPOE_MTU;
+	if (conn->mtu > ETH_PPPOE_MTU)
+	    conn->mtu = ETH_PPPOE_MTU;
+	if (conn->mru > ETH_PPPOE_MTU)
+	    conn->mru = ETH_PPPOE_MTU;
     }
 
     /* We're done. */
diff --git a/pppd/plugins/pppoe/plugin.c b/pppd/plugins/pppoe/plugin.c
index 5732460..e9353eb 100644
--- a/pppd/plugins/pppoe/plugin.c
+++ b/pppd/plugins/pppoe/plugin.c
@@ -161,8 +161,8 @@ PPPOEConnectDevice(void)
     }
 
     /* Restore configuration */
-    lcp_allowoptions[0].mru = conn->mtu;
-    lcp_wantoptions[0].mru = conn->mru;
+    lcp_allowoptions[0].mru = conn->mtu = conn->storedmtu;
+    lcp_wantoptions[0].mru = conn->mru = conn->storedmru;
 
     /* Update maximum MRU */
     s = socket(AF_INET, SOCK_DGRAM, 0);
@@ -179,9 +179,9 @@ PPPOEConnectDevice(void)
     close(s);
 
     if (lcp_allowoptions[0].mru > ifr.ifr_mtu - TOTAL_OVERHEAD)
-	lcp_allowoptions[0].mru = ifr.ifr_mtu - TOTAL_OVERHEAD;
+	lcp_allowoptions[0].mru = conn->mtu = ifr.ifr_mtu - TOTAL_OVERHEAD;
     if (lcp_wantoptions[0].mru > ifr.ifr_mtu - TOTAL_OVERHEAD)
-	lcp_wantoptions[0].mru = ifr.ifr_mtu - TOTAL_OVERHEAD;
+	lcp_wantoptions[0].mru = conn->mru = ifr.ifr_mtu - TOTAL_OVERHEAD;
 
     if (pppoe_host_uniq) {
 	if (!parseHostUniq(pppoe_host_uniq, &conn->hostUniq))
@@ -217,11 +217,17 @@ PPPOEConnectDevice(void)
 	    goto errout;
 	}
 	discovery1(conn);
+	/* discovery1() may update conn->mtu and conn->mru */
+	lcp_allowoptions[0].mru = conn->mtu;
+	lcp_wantoptions[0].mru = conn->mru;
 	if (conn->discoveryState != STATE_RECEIVED_PADO) {
 	    error("Unable to complete PPPoE Discovery phase 1");
 	    goto errout;
 	}
 	discovery2(conn);
+	/* discovery2() may update conn->mtu and conn->mru */
+	lcp_allowoptions[0].mru = conn->mtu;
+	lcp_wantoptions[0].mru = conn->mru;
 	if (conn->discoveryState != STATE_SESSION) {
 	    error("Unable to complete PPPoE Discovery phase 2");
 	    goto errout;
@@ -452,8 +458,8 @@ void pppoe_check_options(void)
 	lcp_wantoptions[0].mru = MAX_PPPOE_MTU;
 
     /* Save configuration */
-    conn->mtu = lcp_allowoptions[0].mru;
-    conn->mru = lcp_wantoptions[0].mru;
+    conn->storedmtu = lcp_allowoptions[0].mru;
+    conn->storedmru = lcp_wantoptions[0].mru;
 
     ccp_allowoptions[0].deflate = 0;
     ccp_wantoptions[0].deflate = 0;
diff --git a/pppd/plugins/pppoe/pppoe.h b/pppd/plugins/pppoe/pppoe.h
index a72454e..60c4f5e 100644
--- a/pppd/plugins/pppoe/pppoe.h
+++ b/pppd/plugins/pppoe/pppoe.h
@@ -242,8 +242,10 @@ typedef struct PPPoEConnectionStruct {
     int discoveryTimeout;       /* Timeout for discovery packets */
     int discoveryAttempts;      /* Number of discovery attempts */
     int seenMaxPayload;
-    int mtu;			/* Stored MTU */
-    int mru;			/* Stored MRU */
+    int storedmtu;		/* Stored MTU */
+    int storedmru;		/* Stored MRU */
+    int mtu;
+    int mru;
 } PPPoEConnection;
 
 /* Structure used to determine acceptable PADO or PADS packet */