sd-rtnl: message_addr - expose a few more getters

[elogind.git] / src / libsystemd / sd-rtnl / rtnl-message.c

diff --git a/src/libsystemd/sd-rtnl/rtnl-message.c b/src/libsystemd/sd-rtnl/rtnl-message.c
index edf567235480825dee4fbcab90be551fdc82b199..fc71ed90183c4547a2ccbf604c6651c09f595c88 100644 (file)
--- a/src/libsystemd/sd-rtnl/rtnl-message.c
+++ b/src/libsystemd/sd-rtnl/rtnl-message.c
@@ -259,6 +259,66 @@ int sd_rtnl_message_addr_set_scope(sd_rtnl_message *m, unsigned char scope) {
         return 0;
 }
 
+int sd_rtnl_message_addr_get_family(sd_rtnl_message *m, unsigned char *family) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(family, -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        *family = ifa->ifa_family;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_get_scope(sd_rtnl_message *m, unsigned char *scope) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(scope, -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        *scope = ifa->ifa_scope;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_get_flags(sd_rtnl_message *m, unsigned char *flags) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(flags, -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        *flags = ifa->ifa_flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_get_ifindex(sd_rtnl_message *m, int *ifindex) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(ifindex, -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        *ifindex = ifa->ifa_index;
+
+        return 0;
+}
+
 int sd_rtnl_message_new_addr(sd_rtnl *rtnl, sd_rtnl_message **ret,
                              uint16_t nlmsg_type, int index,
                              unsigned char family) {
@@ -1019,12 +1079,17 @@ int socket_write_message(sd_rtnl *nl, sd_rtnl_message *m) {
  */
 int socket_read_message(sd_rtnl *rtnl) {
         _cleanup_free_ void *buffer = NULL;
+        uint8_t cred_buffer[CMSG_SPACE(sizeof(struct ucred))];
+        struct iovec iov = {};
+        struct msghdr msg = {
+                .msg_iov = &iov,
+                .msg_iovlen = 1,
+                .msg_control = cred_buffer,
+                .msg_controllen = sizeof(cred_buffer),
+        };
+        struct cmsghdr *cmsg;
+        bool auth = false;
         struct nlmsghdr *new_msg;
-        union {
-                struct sockaddr sa;
-                struct sockaddr_nl nl;
-        } addr;
-        socklen_t addr_len = sizeof(addr);
         size_t need, len;
         int r, ret = 0;
 
@@ -1038,19 +1103,37 @@ int socket_read_message(sd_rtnl *rtnl) {
         if (!buffer)
                 return -ENOMEM;
 
-        r = recvfrom(rtnl->fd, buffer, need, 0, &addr.sa, &addr_len);
+        iov.iov_base = buffer;
+        iov.iov_len = need;
+
+        r = recvmsg(rtnl->fd, &msg, 0);
         if (r < 0)
-                return (errno == EAGAIN) ? 0 : -errno; /* no data */
+                /* no data */
+                return (errno == EAGAIN) ? 0 : -errno;
         else if (r == 0)
-                return -ECONNRESET; /* connection was closed by the kernel */
-        else if (addr_len != sizeof(addr.nl) ||
-                        addr.nl.nl_family != AF_NETLINK)
-                return -EIO; /* not a netlink message */
-        else if (addr.nl.nl_pid != 0)
-                return 0; /* not from the kernel */
+                /* connection was closed by the kernel */
+                return -ECONNRESET;
         else
                 len = (size_t)r;
 
+        for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+                if (cmsg->cmsg_level == SOL_SOCKET &&
+                    cmsg->cmsg_type == SCM_CREDENTIALS &&
+                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
+                        struct ucred *ucred = (void *)CMSG_DATA(cmsg);
+
+                        /* from the kernel */
+                        if (ucred->uid == 0 && ucred->pid == 0) {
+                                auth = true;
+                                break;
+                        }
+                }
+        }
+
+        if (!auth)
+                /* not from the kernel, ignore */
+                return 0;
+
         for (new_msg = buffer; NLMSG_OK(new_msg, len); new_msg = NLMSG_NEXT(new_msg, len)) {
                 _cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL;
                 const NLType *nl_type;