This patch is to follow RFC3021 which allows to use 31-bit mask
in point-to-point link.
If a 31-bit subnet mask is assigned to a point-to-point link, it
leaves the <Host-number> with only 1 bit. Consequently, only two
possible addresses may result:
{<Network-number>, 0} and {<Network-number>, -1}
These addresses have historically been associated with network and
broadcast addresses (see Section 2.2). In a point-to-point link with
a 31-bit subnet mask, the two addresses above MUST be interpreted as
host addresses.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Fu Siyuan <[email protected]>
Cc: Wu Jiaxin <[email protected]>
Cc: Ye Ting <[email protected]>
---
MdeModulePkg/Include/Library/NetLib.h | 6 ++++--
MdeModulePkg/Library/DxeNetLib/DxeNetLib.c | 14 ++++++++++----
MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Common.c | 20 +++++++++++++-------
3 files changed, 27 insertions(+), 13 deletions(-)
diff --git a/MdeModulePkg/Include/Library/NetLib.h
b/MdeModulePkg/Include/Library/NetLib.h
index 4cd4227..b9df46c 100644
--- a/MdeModulePkg/Include/Library/NetLib.h
+++ b/MdeModulePkg/Include/Library/NetLib.h
@@ -414,8 +414,10 @@ NetGetIpClass (
ASSERT if NetMask is zero.
- If all bits of the host address of IP are 0 or 1, IP is also not a valid
unicast address.
-
+ If all bits of the host address of IP are 0 or 1, IP is also not a valid
unicast address,
+ except when the originator is one of the endpoints of a point-to-point link
with a 31-bit
+ mask (RFC3021).
+
@param[in] Ip The IP to check against.
@param[in] NetMask The mask of the IP.
diff --git a/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c
b/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c
index 1ee77fe..b8544b8 100644
--- a/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c
+++ b/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c
@@ -637,7 +637,9 @@ NetGetIpClass (
ASSERT if NetMask is zero.
- If all bits of the host address of IP are 0 or 1, IP is also not a valid
unicast address.
+ If all bits of the host address of IP are 0 or 1, IP is also not a valid
unicast address,
+ except when the originator is one of the endpoints of a point-to-point link
with a 31-bit
+ mask (RFC3021).
@param[in] Ip The IP to check against.
@param[in] NetMask The mask of the IP.
@@ -657,9 +659,13 @@ NetIp4IsUnicast (
if (Ip == 0 || IP4_IS_LOCAL_BROADCAST (Ip)) {
return FALSE;
}
-
- if (((Ip &~NetMask) == ~NetMask) || ((Ip &~NetMask) == 0)) {
- return FALSE;
+
+ if (NetGetMaskLength (NetMask) != 31) {
+ if (((Ip &~NetMask) == ~NetMask) || ((Ip &~NetMask) == 0)) {
+ return FALSE;
+ }
+ } else {
+ return TRUE;
}
return TRUE;
diff --git a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Common.c
b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Common.c
index 7c7d182..b8160c1 100644
--- a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Common.c
+++ b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Common.c
@@ -314,16 +314,22 @@ Ip4StationAddressValid (
//
// Station address can't be subnet broadcast/net broadcast address
+ // RFC3021: In a point-to-point network with 31-bit mask, the <Host-number>
only has
+ // 1 bit, only two possible addresses may result:
+ // {<Network-number>, 0} and {<Network-number>, -1}
+ // The two address above must be interpreted as host addresses.
//
- if ((Ip == (Ip & Netmask)) || (Ip == (Ip | ~Netmask))) {
- return FALSE;
- }
+ if (Len != 31) {
+ if ((Ip == (Ip & Netmask)) || (Ip == (Ip | ~Netmask))) {
+ return FALSE;
+ }
- NetBrdcastMask = gIp4AllMasks[MIN (Len, Type << 3)];
+ NetBrdcastMask = gIp4AllMasks[MIN (Len, Type << 3)];
- if (Ip == (Ip | ~NetBrdcastMask)) {
- return FALSE;
+ if (Ip == (Ip | ~NetBrdcastMask)) {
+ return FALSE;
+ }
}
return TRUE;
-}
\ No newline at end of file
+}
--
1.9.5.msysgit.1
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