git: 796d9b45c7c9 - stable/12 - MFC r365628 by ae: Fix compatibility regression after r364117.

[Gordon Bergling]

The branch stable/12 has been updated by gbe (doc committer):

URL: https://cgit.FreeBSD.org/src/commit/?id=796d9b45c7c917f0fd09e7c578e8189932debae5

commit 796d9b45c7c917f0fd09e7c578e8189932debae5
Author:     Andrey V. Elsukov <ae at FreeBSD.org>
AuthorDate: 2020-09-11 10:07:09 +0000
Commit:     Gordon Bergling <gbe at FreeBSD.org>
CommitDate: 2021-01-03 13:27:50 +0000

    MFC r365628 by ae: Fix compatibility regression after r364117.
    
    Properly handle the case, when some opcode keywords follow after
    the `frag` opcode without additional options.
    
    Reported by:    Evgeniy Khramtsov <evgeniy at khramtsov org>
    Approved by:    glebius
    
    (cherry picked from commit b876085f5589f4e6d531d97ad902c5730ec55339)
---
 sbin/ipfw/ipfw2.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/sbin/ipfw/ipfw2.c b/sbin/ipfw/ipfw2.c
index e0b5371adb91..85347b1add03 100644
--- a/sbin/ipfw/ipfw2.c
+++ b/sbin/ipfw/ipfw2.c
@@ -4560,17 +4560,24 @@ read_options:
 			fill_cmd(cmd, O_DIVERTED, 0, 2);
 			break;
 
-		case TOK_FRAG:
-			fill_flags_cmd(cmd, O_FRAG, f_ipoff, *av);
-			/*
-			 * Compatibility: no argument after "frag"
-			 * keyword equals to "frag offset".
-			 */
-			if (cmd->arg1 == 0)
-				cmd->arg1 = 0x1;
-			else
+		case TOK_FRAG: {
+			uint32_t set = 0, clear = 0;
+
+			if (*av != NULL && fill_flags(f_ipoff, *av, NULL,
+			    &set, &clear) == 0)
 				av++;
+			else {
+				/*
+				 * Compatibility: no argument after "frag"
+				 * keyword equals to "frag offset".
+				 */
+				set = 0x01;
+				clear = 0;
+			}
+			fill_cmd(cmd, O_FRAG, 0,
+			    (set & 0xff) | ( (clear & 0xff) << 8));
 			break;
+		}
 
 		case TOK_LAYER2:
 			fill_cmd(cmd, O_LAYER2, 0, 0);