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busybox: add support for CHECKSUM_PARTIAL to udhcpc

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When running as KVM or Xen guest, packets may be received with
incomplete checksum[1].  Patch adopted from Fedora dhcp package.

[1]. http://article.gmane.org/gmane.linux.kernel/1003853

Signed-off-by: Alexey I. Froloff <raorn@raorn.name>

SVN-Revision: 33475
This commit is contained in:
Florian Fainelli 2012-09-19 15:13:38 +00:00
parent 57bd95734d
commit 9e504b31a4
2 changed files with 88 additions and 1 deletions
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2
package/busybox/Makefile
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@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
PKG_NAME:=busybox
PKG_VERSION:=1.19.4
PKG_RELEASE:=4
PKG_RELEASE:=5
PKG_FLAGS:=essential
PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2

87
package/busybox/patches/950-partial-checksum.patch Normal file
View file

@ -0,0 +1,87 @@
diff -ur busybox-1.19.4.orig/networking/udhcp/dhcpc.c busybox-1.19.4/networking/udhcp/dhcpc.c
--- busybox-1.19.4.orig/networking/udhcp/dhcpc.c 2012-09-06 22:33:53.476998721 +0400
+++ busybox-1.19.4/networking/udhcp/dhcpc.c 2012-09-07 01:09:46.693372304 +0400
@@ -26,8 +26,8 @@
#include "dhcpc.h"
#include <netinet/if_ether.h>
-#include <netpacket/packet.h>
#include <linux/filter.h>
+#include <linux/if_packet.h>
/* struct client_config_t client_config is in bb_common_bufsiz1 */
@@ -784,17 +784,41 @@
static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
{
int bytes;
+ int nocsum = 0;
struct ip_udp_dhcp_packet packet;
uint16_t check;
+ unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
+ struct iovec iov = {
+ .iov_base = &packet,
+ .iov_len = sizeof(packet),
+ };
+ struct msghdr msg = {
+ .msg_iov = &iov,
+ .msg_iovlen = 1,
+ .msg_control = cmsgbuf,
+ .msg_controllen = sizeof(cmsgbuf),
+ };
+ struct cmsghdr *cmsg;
memset(&packet, 0, sizeof(packet));
- bytes = safe_read(fd, &packet, sizeof(packet));
+ do {
+ bytes = recvmsg(fd, &msg, 0);
+ } while (bytes < 0 && errno == EINTR);
+
if (bytes < 0) {
log1("Packet read error, ignoring");
/* NB: possible down interface, etc. Caller should pause. */
return bytes; /* returns -1 */
}
+ for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+ if (cmsg->cmsg_level == SOL_PACKET &&
+ cmsg->cmsg_type == PACKET_AUXDATA) {
+ struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
+ nocsum = aux->tp_status & TP_STATUS_CSUMNOTREADY;
+ }
+ }
+
if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
log1("Packet is too short, ignoring");
return -2;
@@ -834,7 +858,7 @@
packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
check = packet.udp.check;
packet.udp.check = 0;
- if (check && check != udhcp_checksum(&packet, bytes)) {
+ if (!nocsum && check && check != udhcp_checksum(&packet, bytes)) {
log1("Packet with bad UDP checksum received, ignoring");
return -2;
}
@@ -880,6 +904,7 @@
{
int fd;
struct sockaddr_ll sock;
+ int val;
/*
* Comment:
@@ -946,6 +971,13 @@
log1("Attached filter to raw socket fd %d", fd); // log?
}
+ val = 1;
+ if (setsockopt(fd, SOL_PACKET, PACKET_AUXDATA, &val,
+ sizeof(val)) < 0) {
+ if (errno != ENOPROTOOPT)
+ log1("Failed to set auxiliary packet data for socket fd %d", fd);
+ }
+
log1("Created raw socket");
return fd;