diff options
| -rw-r--r-- | networking/udhcp/dhcpc.c | 57 |
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"); |