Tools: hv: kvp: use misc char device to communicate with kernel

Use /dev/vmbus/hv_kvp instead of netlink.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: Alex Ng <alexng@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index 408bb076a23419e37ad604d0901496ae17745341..0d9f48ec42bbb66366d1b35dab04af94eb152901 100644 (file)
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -33,7 +33,6 @@
 #include <ctype.h>
 #include <errno.h>
 #include <arpa/inet.h>
-#include <linux/connector.h>
 #include <linux/hyperv.h>
 #include <linux/netlink.h>
 #include <ifaddrs.h>
@@ -79,7 +78,6 @@ enum {
        DNS
 };
 
-static struct sockaddr_nl addr;
 static int in_hand_shake = 1;
 
 static char *os_name = "";
@@ -1387,34 +1385,6 @@ kvp_get_domain_name(char *buffer, int length)
        freeaddrinfo(info);
 }
 
-static int
-netlink_send(int fd, struct cn_msg *msg)
-{
-       struct nlmsghdr nlh = { .nlmsg_type = NLMSG_DONE };
-       unsigned int size;
-       struct msghdr message;
-       struct iovec iov[2];
-
-       size = sizeof(struct cn_msg) + msg->len;
-
-       nlh.nlmsg_pid = getpid();
-       nlh.nlmsg_len = NLMSG_LENGTH(size);
-
-       iov[0].iov_base = &nlh;
-       iov[0].iov_len = sizeof(nlh);
-
-       iov[1].iov_base = msg;
-       iov[1].iov_len = size;
-
-       memset(&message, 0, sizeof(message));
-       message.msg_name = &addr;
-       message.msg_namelen = sizeof(addr);
-       message.msg_iov = iov;
-       message.msg_iovlen = 2;
-
-       return sendmsg(fd, &message, 0);
-}
-
 void print_usage(char *argv[])
 {
        fprintf(stderr, "Usage: %s [options]\n"
@@ -1425,22 +1395,17 @@ void print_usage(char *argv[])
 
 int main(int argc, char *argv[])
 {
-       int fd, len, nl_group;
+       int kvp_fd, len;
        int error;
-       struct cn_msg *message;
        struct pollfd pfd;
-       struct nlmsghdr *incoming_msg;
-       struct cn_msg   *incoming_cn_msg;
-       struct hv_kvp_msg *hv_msg;
-       char    *p;
+       char    *p;
+       struct hv_kvp_msg hv_msg[1];
        char    *key_value;
        char    *key_name;
        int     op;
        int     pool;
        char    *if_name;
        struct hv_kvp_ipaddr_value *kvp_ip_val;
-       char *kvp_recv_buffer;
-       size_t kvp_recv_buffer_len;
        int daemonize = 1, long_index = 0, opt;
 
        static struct option long_options[] = {
@@ -1468,12 +1433,14 @@ int main(int argc, char *argv[])
        openlog("KVP", 0, LOG_USER);
        syslog(LOG_INFO, "KVP starting; pid is:%d", getpid());
 
-       kvp_recv_buffer_len = NLMSG_LENGTH(0) + sizeof(struct cn_msg) + sizeof(struct hv_kvp_msg);
-       kvp_recv_buffer = calloc(1, kvp_recv_buffer_len);
-       if (!kvp_recv_buffer) {
-               syslog(LOG_ERR, "Failed to allocate netlink buffer");
+       kvp_fd = open("/dev/vmbus/hv_kvp", O_RDWR);
+
+       if (kvp_fd < 0) {
+               syslog(LOG_ERR, "open /dev/vmbus/hv_kvp failed; error: %d %s",
+                       errno, strerror(errno));
                exit(EXIT_FAILURE);
        }
+
        /*
         * Retrieve OS release information.
         */
@@ -1489,100 +1456,44 @@ int main(int argc, char *argv[])
                exit(EXIT_FAILURE);
        }
 
-       fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
-       if (fd < 0) {
-               syslog(LOG_ERR, "netlink socket creation failed; error: %d %s", errno,
-                               strerror(errno));
-               exit(EXIT_FAILURE);
-       }
-       addr.nl_family = AF_NETLINK;
-       addr.nl_pad = 0;
-       addr.nl_pid = 0;
-       addr.nl_groups = 0;
-
-
-       error = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
-       if (error < 0) {
-               syslog(LOG_ERR, "bind failed; error: %d %s", errno, strerror(errno));
-               close(fd);
-               exit(EXIT_FAILURE);
-       }
-       nl_group = CN_KVP_IDX;
-
-       if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) {
-               syslog(LOG_ERR, "setsockopt failed; error: %d %s", errno, strerror(errno));
-               close(fd);
-               exit(EXIT_FAILURE);
-       }
-
        /*
         * Register ourselves with the kernel.
         */
-       message = (struct cn_msg *)kvp_recv_buffer;
-       message->id.idx = CN_KVP_IDX;
-       message->id.val = CN_KVP_VAL;
-
-       hv_msg = (struct hv_kvp_msg *)message->data;
        hv_msg->kvp_hdr.operation = KVP_OP_REGISTER1;
-       message->ack = 0;
-       message->len = sizeof(struct hv_kvp_msg);
-
-       len = netlink_send(fd, message);
-       if (len < 0) {
-               syslog(LOG_ERR, "netlink_send failed; error: %d %s", errno, strerror(errno));
-               close(fd);
+       len = write(kvp_fd, hv_msg, sizeof(struct hv_kvp_msg));
+       if (len != sizeof(struct hv_kvp_msg)) {
+               syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
+                      errno, strerror(errno));
+               close(kvp_fd);
                exit(EXIT_FAILURE);
        }
 
-       pfd.fd = fd;
+       pfd.fd = kvp_fd;
 
        while (1) {
-               struct sockaddr *addr_p = (struct sockaddr *) &addr;
-               socklen_t addr_l = sizeof(addr);
                pfd.events = POLLIN;
                pfd.revents = 0;
 
                if (poll(&pfd, 1, -1) < 0) {
                        syslog(LOG_ERR, "poll failed; error: %d %s", errno, strerror(errno));
                        if (errno == EINVAL) {
-                               close(fd);
+                               close(kvp_fd);
                                exit(EXIT_FAILURE);
                        }
                        else
                                continue;
                }
 
-               len = recvfrom(fd, kvp_recv_buffer, kvp_recv_buffer_len, 0,
-                               addr_p, &addr_l);
-
-               if (len < 0) {
-                       int saved_errno = errno;
-                       syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
-                                       addr.nl_pid, errno, strerror(errno));
+               len = read(kvp_fd, hv_msg, sizeof(struct hv_kvp_msg));
 
-                       if (saved_errno == ENOBUFS) {
-                               syslog(LOG_ERR, "receive error: ignored");
-                               continue;
-                       }
+               if (len != sizeof(struct hv_kvp_msg)) {
+                       syslog(LOG_ERR, "read failed; error:%d %s",
+                              errno, strerror(errno));
 
-                       close(fd);
-                       return -1;
+                       close(kvp_fd);
+                       return EXIT_FAILURE;
                }
 
-               if (addr.nl_pid) {
-                       syslog(LOG_WARNING, "Received packet from untrusted pid:%u",
-                                       addr.nl_pid);
-                       continue;
-               }
-
-               incoming_msg = (struct nlmsghdr *)kvp_recv_buffer;
-
-               if (incoming_msg->nlmsg_type != NLMSG_DONE)
-                       continue;
-
-               incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
-               hv_msg = (struct hv_kvp_msg *)incoming_cn_msg->data;
-
                /*
                 * We will use the KVP header information to pass back
                 * the error from this daemon. So, first copy the state
@@ -1603,7 +1514,7 @@ int main(int argc, char *argv[])
                        if (lic_version) {
                                strcpy(lic_version, p);
                                syslog(LOG_INFO, "KVP LIC Version: %s",
-                                       lic_version);
+                                      lic_version);
                        } else {
                                syslog(LOG_ERR, "malloc failed");
                        }
@@ -1702,7 +1613,6 @@ int main(int argc, char *argv[])
                        goto kvp_done;
                }
 
-               hv_msg = (struct hv_kvp_msg *)incoming_cn_msg->data;
                key_name = (char *)hv_msg->body.kvp_enum_data.data.key;
                key_value = (char *)hv_msg->body.kvp_enum_data.data.value;
 
@@ -1753,31 +1663,17 @@ int main(int argc, char *argv[])
                        hv_msg->error = HV_S_CONT;
                        break;
                }
-               /*
-                * Send the value back to the kernel. The response is
-                * already in the receive buffer. Update the cn_msg header to
-                * reflect the key value that has been added to the message
-                */
-kvp_done:
-
-               incoming_cn_msg->id.idx = CN_KVP_IDX;
-               incoming_cn_msg->id.val = CN_KVP_VAL;
-               incoming_cn_msg->ack = 0;
-               incoming_cn_msg->len = sizeof(struct hv_kvp_msg);
-
-               len = netlink_send(fd, incoming_cn_msg);
-               if (len < 0) {
-                       int saved_errno = errno;
-                       syslog(LOG_ERR, "net_link send failed; error: %d %s", errno,
-                                       strerror(errno));
-
-                       if (saved_errno == ENOMEM || saved_errno == ENOBUFS) {
-                               syslog(LOG_ERR, "send error: ignored");
-                               continue;
-                       }
 
+               /* Send the value back to the kernel. */
+kvp_done:
+               len = write(kvp_fd, hv_msg, sizeof(struct hv_kvp_msg));
+               if (len != sizeof(struct hv_kvp_msg)) {
+                       syslog(LOG_ERR, "write failed; error: %d %s", errno,
+                              strerror(errno));
                        exit(EXIT_FAILURE);
                }
        }
 
+       close(kvp_fd);
+       exit(0);
 }