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authorAlexey Froloff <raorn@raorn.name>2012-09-17 14:02:44 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2012-09-17 14:02:44 (GMT)
commit3c62bbae94642e6d05bc9f900bbdb5173d26cc51 (patch)
tree0caa4a0c8745fd92c2383625a1a315e0d313ac43
parent0ffd63ca9a46d1e9112e12702e4337195eade25d (diff)
downloadbusybox-3c62bbae94642e6d05bc9f900bbdb5173d26cc51.tar.gz
busybox-3c62bbae94642e6d05bc9f900bbdb5173d26cc51.tar.bz2
ushcpc: gracefully handle packets with CHECKSUM_PARTIAL
function old new delta udhcp_recv_raw_packet 415 579 +164 change_listen_mode 317 370 +53 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 2/0 up/down: 217/0) Total: 217 bytes Signed-off-by: Alexey Froloff <raorn@raorn.name> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--networking/udhcp/dhcpc.c57
1 files changed, 49 insertions, 8 deletions
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index bc1db70..dcb7d42 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -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 */
@@ -836,12 +836,31 @@ static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
int bytes;
struct ip_udp_dhcp_packet packet;
uint16_t check;
+ unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
+ struct iovec iov;
+ struct msghdr msg;
+ struct cmsghdr *cmsg;
- bytes = safe_read(fd, &packet, sizeof(packet));
- if (bytes < 0) {
- log1("Packet read error, ignoring");
- /* NB: possible down interface, etc. Caller should pause. */
- return bytes; /* returns -1 */
+ /* used to use just safe_read(fd, &packet, sizeof(packet))
+ * but we need to check for TP_STATUS_CSUMNOTREADY :(
+ */
+ iov.iov_base = &packet;
+ iov.iov_len = sizeof(packet);
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ msg.msg_control = cmsgbuf;
+ msg.msg_controllen = sizeof(cmsgbuf);
+ for (;;) {
+ bytes = recvmsg(fd, &msg, 0);
+ if (bytes < 0) {
+ if (errno == EINTR)
+ continue;
+ log1("Packet read error, ignoring");
+ /* NB: possible down interface, etc. Caller should pause. */
+ return bytes; /* returns -1 */
+ }
+ break;
}
if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
@@ -878,6 +897,20 @@ static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
return -2;
}
+ for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+ if (cmsg->cmsg_level == SOL_PACKET
+ && cmsg->cmsg_type == PACKET_AUXDATA
+ ) {
+ /* some VMs don't checksum UDP and TCP data
+ * they send to the same physical machine,
+ * here we detect this case:
+ */
+ struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
+ if (aux->tp_status & TP_STATUS_CSUMNOTREADY)
+ goto skip_udp_sum_check;
+ }
+ }
+
/* verify UDP checksum. IP header has to be modified for this */
memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
/* ip.xx fields which are not memset: protocol, check, saddr, daddr */
@@ -888,6 +921,7 @@ static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
log1("Packet with bad UDP checksum received, ignoring");
return -2;
}
+ skip_udp_sum_check:
if (packet.data.cookie != htonl(DHCP_MAGIC)) {
bb_info_msg("Packet with bad magic, ignoring");
@@ -983,7 +1017,7 @@ static int udhcp_raw_socket(int ifindex)
log1("Opening raw socket on ifindex %d", ifindex); //log2?
fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
- log1("Got raw socket fd %d", fd); //log2?
+ log1("Got raw socket fd"); //log2?
sock.sll_family = AF_PACKET;
sock.sll_protocol = htons(ETH_P_IP);
@@ -995,7 +1029,14 @@ static int udhcp_raw_socket(int ifindex)
/* Ignoring error (kernel may lack support for this) */
if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
sizeof(filter_prog)) >= 0)
- log1("Attached filter to raw socket fd %d", fd); // log?
+ log1("Attached filter to raw socket fd"); // log?
+ }
+
+ if (setsockopt(fd, SOL_PACKET, PACKET_AUXDATA,
+ &const_int_1, sizeof(int)) < 0
+ ) {
+ if (errno != ENOPROTOOPT)
+ log1("Can't set PACKET_AUXDATA on raw socket");
}
log1("Created raw socket");