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 <[email protected]> --- package/busybox/patches/950-partial-checksum.patch | 87 ++++++++++++++++++++ 1 files changed, 87 insertions(+), 0 deletions(-) create mode 100644 package/busybox/patches/950-partial-checksum.patch diff --git a/package/busybox/patches/950-partial-checksum.patch b/package/busybox/patches/950-partial-checksum.patch new file mode 100644 index 0000000..e595162 --- /dev/null +++ b/package/busybox/patches/950-partial-checksum.patch @@ -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; -- 1.7.3.4 _______________________________________________ openwrt-devel mailing list [email protected] https://lists.openwrt.org/mailman/listinfo/openwrt-devel
