klibc-bot for KUMAAN
2012-May-22 09:00 UTC
[klibc] [klibc:master] ipconfig: Append padding if DHCP packet length < 300 octets
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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