Allow to set the DF bit behaviour for outgoing IPv4 packets: it can be
always on, inherited from the inner header, or, by default, always off,
which is the current behaviour.
Signed-off-by: Stefano Brivio <sbri...@redhat.com>
---
include/uapi/linux/if_link.h | 9 +++++++++
ip/iplink_vxlan.c | 29 +++++++++++++++++++++++++++++
man/man8/ip-link.8.in | 14 ++++++++++++++
3 files changed, 52 insertions(+)
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 9c254603ebda..4caf683ce546 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -530,6 +530,7 @@ enum {
IFLA_VXLAN_LABEL,
IFLA_VXLAN_GPE,
IFLA_VXLAN_TTL_INHERIT,
+ IFLA_VXLAN_DF,
__IFLA_VXLAN_MAX
};
#define IFLA_VXLAN_MAX (__IFLA_VXLAN_MAX - 1)
@@ -539,6 +540,14 @@ struct ifla_vxlan_port_range {
__be16 high;
};
+enum ifla_vxlan_df {
+ VXLAN_DF_UNSET = 0,
+ VXLAN_DF_SET,
+ VXLAN_DF_INHERIT,
+ __VXLAN_DF_END,
+ VXLAN_DF_MAX = __VXLAN_DF_END - 1,
+};
+
/* GENEVE section */
enum {
IFLA_GENEVE_UNSPEC,
diff --git a/ip/iplink_vxlan.c b/ip/iplink_vxlan.c
index 7fc0e2b4eb06..86afbe1334f0 100644
--- a/ip/iplink_vxlan.c
+++ b/ip/iplink_vxlan.c
@@ -31,6 +31,7 @@ static void print_explain(FILE *f)
" [ local ADDR ]\n"
" [ ttl TTL ]\n"
" [ tos TOS ]\n"
+ " [ df DF ]\n"
" [ flowlabel LABEL ]\n"
" [ dev PHYS_DEV ]\n"
" [ dstport PORT ]\n"
@@ -52,6 +53,7 @@ static void print_explain(FILE *f)
" ADDR := { IP_ADDRESS | any }\n"
" TOS := { NUMBER | inherit }\n"
" TTL := { 1..255 | auto | inherit }\n"
+ " DF := { unset | set | inherit }\n"
" LABEL := 0-1048575\n"
);
}
@@ -170,6 +172,22 @@ static int vxlan_parse_opt(struct link_util *lu, int argc,
char **argv,
} else
tos = 1;
addattr8(n, 1024, IFLA_VXLAN_TOS, tos);
+ } else if (!matches(*argv, "df")) {
+ enum ifla_vxlan_df df;
+
+ NEXT_ARG();
+ check_duparg(&attrs, IFLA_VXLAN_DF, "df", *argv);
+ if (strcmp(*argv, "unset") == 0)
+ df = VXLAN_DF_UNSET;
+ else if (strcmp(*argv, "set") == 0)
+ df = VXLAN_DF_SET;
+ else if (strcmp(*argv, "inherit") == 0)
+ df = VXLAN_DF_INHERIT;
+ else
+ invarg("DF must be 'unset', 'set' or 'inherit'",
+ *argv);
+
+ addattr8(n, 1024, IFLA_VXLAN_DF, df);
} else if (!matches(*argv, "label") ||
!matches(*argv, "flowlabel")) {
__u32 uval;
@@ -538,6 +556,17 @@ static void vxlan_print_opt(struct link_util *lu, FILE *f,
struct rtattr *tb[])
print_string(PRINT_FP, NULL, "ttl %s ", "auto");
}
+ if (tb[IFLA_VXLAN_DF]) {
+ enum ifla_vxlan_df df = rta_getattr_u8(tb[IFLA_VXLAN_DF]);
+
+ if (df == VXLAN_DF_UNSET)
+ print_string(PRINT_JSON, "df", "df %s ", "unset");
+ else if (df == VXLAN_DF_SET)
+ print_string(PRINT_ANY, "df", "df %s ", "set");
+ else if (df == VXLAN_DF_INHERIT)
+ print_string(PRINT_ANY, "df", "df %s ", "inherit");
+ }
+
if (tb[IFLA_VXLAN_LABEL]) {
__u32 label = rta_getattr_u32(tb[IFLA_VXLAN_LABEL]);
diff --git a/man/man8/ip-link.8.in b/man/man8/ip-link.8.in
index 5132f514b279..1b899dd06b92 100644
--- a/man/man8/ip-link.8.in
+++ b/man/man8/ip-link.8.in
@@ -496,6 +496,8 @@ the following additional arguments are supported:
] [
.BI tos " TOS "
] [
+.BI df " DF "
+] [
.BI flowlabel " FLOWLABEL "
] [
.BI dstport " PORT "
@@ -565,6 +567,18 @@ parameter.
.BI tos " TOS"
- specifies the TOS value to use in outgoing packets.
+.sp
+.BI df " DF"
+- specifies the usage of the DF bit in outgoing packets with IPv4 headers.
+The value
+.B inherit
+causes the bit to be copied from the original IP header. The values
+.B unset
+and
+.B set
+cause the bit to be always unset or always set, respectively. By default, the
+bit is not set.
+
.sp
.BI flowlabel " FLOWLABEL"
- specifies the flow label to use in outgoing packets.
--
2.19.1
