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Index: sys/netinet/tcp.h
===================================================================
RCS file: /home/ncvs/src/sys/netinet/tcp.h,v
retrieving revision 1.40
diff -p -u -I__FBSDID -I$FreeBSD -r1.40 tcp.h
--- sys/netinet/tcp.h 25 May 2007 21:28:49 -0000 1.40
+++ sys/netinet/tcp.h 18 Jun 2008 05:36:20 -0000
@@ -78,6 +78,8 @@ struct tcphdr {
#define TCPOPT_EOL 0
#define TCPOLEN_EOL 1
+#define TCPOPT_PAD 0 /* padding after EOL */
+#define TCPOLEN_PAD 1
#define TCPOPT_NOP 1
#define TCPOLEN_NOP 1
#define TCPOPT_MAXSEG 2
Index: sys/netinet/tcp_output.c
===================================================================
RCS file: /home/ncvs/src/sys/netinet/tcp_output.c,v
retrieving revision 1.141.2.3
diff -p -u -I__FBSDID -I$FreeBSD -r1.141.2.3 tcp_output.c
--- sys/netinet/tcp_output.c 5 Dec 2007 10:37:17 -0000 1.141.2.3
+++ sys/netinet/tcp_output.c 18 Jun 2008 05:36:21 -0000
@@ -1280,12 +1280,16 @@ tcp_addoptions(struct tcpopt *to, u_char
for (mask = 1; mask < TOF_MAXOPT; mask <<= 1) {
if ((to->to_flags & mask) != mask)
continue;
+ if (optlen == TCP_MAXOLEN)
+ break;
switch (to->to_flags & mask) {
case TOF_MSS:
while (optlen % 4) {
optlen += TCPOLEN_NOP;
*optp++ = TCPOPT_NOP;
}
+ if (TCP_MAXOLEN - optlen < TCPOLEN_MAXSEG)
+ continue;
optlen += TCPOLEN_MAXSEG;
*optp++ = TCPOPT_MAXSEG;
*optp++ = TCPOLEN_MAXSEG;
@@ -1298,6 +1302,8 @@ tcp_addoptions(struct tcpopt *to, u_char
optlen += TCPOLEN_NOP;
*optp++ = TCPOPT_NOP;
}
+ if (TCP_MAXOLEN - optlen < TCPOLEN_WINDOW)
+ continue;
optlen += TCPOLEN_WINDOW;
*optp++ = TCPOPT_WINDOW;
*optp++ = TCPOLEN_WINDOW;
@@ -1308,6 +1314,8 @@ tcp_addoptions(struct tcpopt *to, u_char
optlen += TCPOLEN_NOP;
*optp++ = TCPOPT_NOP;
}
+ if (TCP_MAXOLEN - optlen < TCPOLEN_SACK_PERMITTED)
+ continue;
optlen += TCPOLEN_SACK_PERMITTED;
*optp++ = TCPOPT_SACK_PERMITTED;
*optp++ = TCPOLEN_SACK_PERMITTED;
@@ -1317,6 +1325,8 @@ tcp_addoptions(struct tcpopt *to, u_char
optlen += TCPOLEN_NOP;
*optp++ = TCPOPT_NOP;
}
+ if (TCP_MAXOLEN - optlen < TCPOLEN_TIMESTAMP)
+ continue;
optlen += TCPOLEN_TIMESTAMP;
*optp++ = TCPOPT_TIMESTAMP;
*optp++ = TCPOLEN_TIMESTAMP;
@@ -1355,7 +1365,7 @@ tcp_addoptions(struct tcpopt *to, u_char
optlen += TCPOLEN_NOP;
*optp++ = TCPOPT_NOP;
}
- if (TCP_MAXOLEN - optlen < 2 + TCPOLEN_SACK)
+ if (TCP_MAXOLEN - optlen < TCPOLEN_SACKHDR + TCPOLEN_SACK)
continue;
optlen += TCPOLEN_SACKHDR;
*optp++ = TCPOPT_SACK;
@@ -1386,9 +1396,15 @@ tcp_addoptions(struct tcpopt *to, u_char
optlen += TCPOLEN_EOL;
*optp++ = TCPOPT_EOL;
}
+ /*
+ * According to RFC 793 (STD0007):
+ * "The content of the header beyond the End-of-Option option
+ * must be header padding (i.e., zero)."
+ * and later: "The padding is composed of zeros."
+ */
while (optlen % 4) {
- optlen += TCPOLEN_NOP;
- *optp++ = TCPOPT_NOP;
+ optlen += TCPOLEN_PAD;
+ *optp++ = TCPOPT_PAD;
}
KASSERT(optlen <= TCP_MAXOLEN, ("%s: TCP options too long", __func__));
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