[klibc] [klibc:master] ipconfig: Append padding if DHCP packet length < 300 octets
klibc-bot for KUMAAN
9maaan at gmail.com
Tue May 22 02:00:03 PDT 2012
Commit-ID: f41c1d74c6a8e3d463e7e4291b112b367eb8b097
Gitweb: http://git.kernel.org/?p=libs/klibc/klibc.git;a=commit;h=f41c1d74c6a8e3d463e7e4291b112b367eb8b097
Author: KUMAAN <9maaan at gmail.com>
AuthorDate: Tue, 23 Aug 2011 14:59:19 +0900
Committer: maximilian attems <max at stro.at>
CommitDate: Tue, 22 May 2012 10:55:16 +0200
[klibc] ipconfig: Append padding if DHCP packet length < 300 octets
This patch appends padding to DHCP packet for its length to be 300 octets,
if its length is shorter than 300 octets.
dhclient in ISC DHCP 4.1.1-P1 also does so. Some bad DHCP servers ignore
short DHCP packet which dhclient doesn't send.
Signed-off-by: KUMAAN <9maaan at gmail.com>
Acked-by: H. Peter Anvin <hpa at zytor.com>
Signed-off-by: maximilian attems <max at stro.at>
---
usr/kinit/ipconfig/bootp_packet.h | 3 +++
usr/kinit/ipconfig/dhcp_proto.c | 18 +++++++++++++++++-
2 files changed, 20 insertions(+), 1 deletions(-)
diff --git a/usr/kinit/ipconfig/bootp_packet.h b/usr/kinit/ipconfig/bootp_packet.h
index 1ef505e..1d5bd0d 100644
--- a/usr/kinit/ipconfig/bootp_packet.h
+++ b/usr/kinit/ipconfig/bootp_packet.h
@@ -38,4 +38,7 @@ struct bootp_hdr {
/* larger size for backward compatibility of ipconfig */
#define BOOTP_EXTS_SIZE 1500
+/* minimum length of BOOTP/DHCP packet on sending */
+#define BOOTP_MIN_LEN 300
+
#endif /* BOOTP_PACKET_H */
diff --git a/usr/kinit/ipconfig/dhcp_proto.c b/usr/kinit/ipconfig/dhcp_proto.c
index 0c907e9..ebf79cc 100644
--- a/usr/kinit/ipconfig/dhcp_proto.c
+++ b/usr/kinit/ipconfig/dhcp_proto.c
@@ -50,7 +50,7 @@ static uint8_t dhcp_end[] = {
/* Both iovecs below have to have the same structure, since dhcp_send()
pokes at the internals */
-#define DHCP_IOV_LEN 7
+#define DHCP_IOV_LEN 8
static struct iovec dhcp_discover_iov[DHCP_IOV_LEN] = {
/* [0] = ip + udp header */
@@ -60,6 +60,7 @@ static struct iovec dhcp_discover_iov[DHCP_IOV_LEN] = {
/* [4] = optional vendor class */
/* [5] = optional hostname */
/* [6] = {dhcp_end, sizeof(dhcp_end)} */
+ /* [7] = optional padding */
};
static struct iovec dhcp_request_iov[DHCP_IOV_LEN] = {
@@ -70,6 +71,7 @@ static struct iovec dhcp_request_iov[DHCP_IOV_LEN] = {
/* [4] = optional vendor class */
/* [5] = optional hostname */
/* [6] = {dhcp_end, sizeof(dhcp_end)} */
+ /* [7] = optional padding */
};
/*
@@ -187,7 +189,10 @@ static int dhcp_send(struct netdev *dev, struct iovec *vec)
{
struct bootp_hdr bootp;
char dhcp_hostname[SYS_NMLN+2];
+ uint8_t padding[BOOTP_MIN_LEN - sizeof(struct bootp_hdr)];
+ int padding_len;
int i = 4;
+ int j;
memset(&bootp, 0, sizeof(struct bootp_hdr));
@@ -232,6 +237,17 @@ static int dhcp_send(struct netdev *dev, struct iovec *vec)
vec[i].iov_base = dhcp_end;
vec[i].iov_len = sizeof(dhcp_end);
+ /* Append padding if DHCP packet length is shorter than BOOTP_MIN_LEN */
+ padding_len = sizeof(padding);
+ for (j = 2; j <= i; j++)
+ padding_len -= vec[j].iov_len;
+ if (padding_len > 0) {
+ memset(padding, 0, padding_len);
+ i++;
+ vec[i].iov_base = padding;
+ vec[i].iov_len = padding_len;
+ }
+
return packet_send(dev, vec, i + 1);
}
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