package/busybox/patches/950-partial-checksum.patch

   1 --- a/networking/udhcp/dhcpc.c
   2 +++ b/networking/udhcp/dhcpc.c
   3 @@ -26,8 +26,8 @@
   4  #include "dhcpc.h"
   5
   6  #include <netinet/if_ether.h>
   7 -#include <netpacket/packet.h>
   8  #include <linux/filter.h>
   9 +#include <linux/if_packet.h>
  10
  11  /* struct client_config_t client_config is in bb_common_bufsiz1 */
  12
  13 @@ -846,17 +846,41 @@ static int send_release(uint32_t server,
  14  static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
  15  {
  16         int bytes;
  17 +       int nocsum = 0;
  18         struct ip_udp_dhcp_packet packet;
  19         uint16_t check;
  20 +       unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
  21 +       struct iovec iov = {
  22 +               .iov_base = &packet,
  23 +               .iov_len = sizeof(packet),
  24 +       };
  25 +       struct msghdr msg = {
  26 +               .msg_iov = &iov,
  27 +               .msg_iovlen = 1,
  28 +               .msg_control = cmsgbuf,
  29 +               .msg_controllen = sizeof(cmsgbuf),
  30 +       };
  31 +       struct cmsghdr *cmsg;
  32
  33         memset(&packet, 0, sizeof(packet));
  34 -       bytes = safe_read(fd, &packet, sizeof(packet));
  35 +       do {
  36 +               bytes = recvmsg(fd, &msg, 0);
  37 +       } while (bytes < 0 && errno == EINTR);
  38 +
  39         if (bytes < 0) {
  40                 log1("Packet read error, ignoring");
  41                 /* NB: possible down interface, etc. Caller should pause. */
  42                 return bytes; /* returns -1 */
  43         }
  44
  45 +       for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
  46 +               if (cmsg->cmsg_level == SOL_PACKET &&
  47 +                       cmsg->cmsg_type == PACKET_AUXDATA) {
  48 +                       struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
  49 +                       nocsum = aux->tp_status & TP_STATUS_CSUMNOTREADY;
  50 +               }
  51 +       }
  52 +
  53         if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
  54                 log1("Packet is too short, ignoring");
  55                 return -2;
  56 @@ -896,7 +920,7 @@ static NOINLINE int udhcp_recv_raw_packe
  57         packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
  58         check = packet.udp.check;
  59         packet.udp.check = 0;
  60 -       if (check && check != udhcp_checksum(&packet, bytes)) {
  61 +       if (!nocsum && check && check != udhcp_checksum(&packet, bytes)) {
  62                 log1("Packet with bad UDP checksum received, ignoring");
  63                 return -2;
  64         }
  65 @@ -942,6 +966,7 @@ static int udhcp_raw_socket(int ifindex)
  66  {
  67         int fd;
  68         struct sockaddr_ll sock;
  69 +       int val;
  70
  71         /*
  72          * Comment:
  73 @@ -1008,6 +1033,13 @@ static int udhcp_raw_socket(int ifindex)
  74                         log1("Attached filter to raw socket fd %d", fd); // log?
  75         }
  76
  77 +       val = 1;
  78 +       if (setsockopt(fd, SOL_PACKET, PACKET_AUXDATA, &val,
  79 +                       sizeof(val)) < 0) {
  80 +               if (errno != ENOPROTOOPT)
  81 +                       log1("Failed to set auxiliary packet data for socket fd %d", fd);
  82 +       }
  83 +
  84         log1("Created raw socket");
  85
  86         return fd;