diff options
Diffstat (limited to 'src/plugins/sflow/sflow_usersock.c')
| -rw-r--r-- | src/plugins/sflow/sflow_usersock.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/src/plugins/sflow/sflow_usersock.c b/src/plugins/sflow/sflow_usersock.c new file mode 100644 index 00000000000..0ccb947709a --- /dev/null +++ b/src/plugins/sflow/sflow_usersock.c @@ -0,0 +1,222 @@ +/* + * Copyright (c) 2024 InMon Corp. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#if defined(__cplusplus) +extern "C" +{ +#endif + +#include <vlib/vlib.h> +#include <vnet/vnet.h> +#include <vnet/pg/pg.h> +#include <vppinfra/error.h> +#include <sflow/sflow.h> + +#include <fcntl.h> +#include <asm/types.h> +#include <sys/socket.h> +#include <linux/types.h> +#include <linux/netlink.h> +#include <signal.h> +#include <ctype.h> + +#include <sflow/sflow_usersock.h> + + /*_________________---------------------------__________________ + _________________ fcntl utils __________________ + -----------------___________________________------------------ + */ + + static void + setNonBlocking (int fd) + { + // set the socket to non-blocking + int fdFlags = fcntl (fd, F_GETFL); + fdFlags |= O_NONBLOCK; + if (fcntl (fd, F_SETFL, fdFlags) < 0) + { + SFLOW_ERR ("fcntl(O_NONBLOCK) failed: %s\n", strerror (errno)); + } + } + + static void + setCloseOnExec (int fd) + { + // make sure it doesn't get inherited, e.g. when we fork a script + int fdFlags = fcntl (fd, F_GETFD); + fdFlags |= FD_CLOEXEC; + if (fcntl (fd, F_SETFD, fdFlags) < 0) + { + SFLOW_ERR ("fcntl(F_SETFD=FD_CLOEXEC) failed: %s\n", strerror (errno)); + } + } + + /*_________________---------------------------__________________ + _________________ usersock_open __________________ + -----------------___________________________------------------ + */ + + static int + usersock_open (void) + { + int nl_sock = socket (AF_NETLINK, SOCK_RAW, NETLINK_USERSOCK); + if (nl_sock < 0) + { + SFLOW_ERR ("nl_sock open failed: %s\n", strerror (errno)); + return -1; + } + setNonBlocking (nl_sock); + setCloseOnExec (nl_sock); + return nl_sock; + } + + /*_________________---------------------------__________________ + _________________ SFLOWUS_open __________________ + -----------------___________________________------------------ + */ + + bool + SFLOWUS_open (SFLOWUS *ust) + { + if (ust->nl_sock == 0) + { + ust->nl_sock = usersock_open (); + } + return true; + } + + /*_________________---------------------------__________________ + _________________ SFLOWUS_close __________________ + -----------------___________________________------------------ + */ + + bool + SFLOWUS_close (SFLOWUS *ust) + { + if (ust->nl_sock != 0) + { + int err = close (ust->nl_sock); + if (err == 0) + { + ust->nl_sock = 0; + return true; + } + else + { + SFLOW_WARN ("SFLOWUS_close: returned %d : %s\n", err, + strerror (errno)); + } + } + return false; + } + + /*_________________---------------------------__________________ + _________________ SFLOWUSSpec_setMsgType __________________ + -----------------___________________________------------------ + */ + + bool + SFLOWUSSpec_setMsgType (SFLOWUSSpec *spec, EnumSFlowVppMsgType msgType) + { + spec->nlh.nlmsg_type = msgType; + return true; + } + + /*_________________---------------------------__________________ + _________________ SFLOWUSSpec_setAttr __________________ + -----------------___________________________------------------ + */ + + bool + SFLOWUSSpec_setAttr (SFLOWUSSpec *spec, EnumSFlowVppAttributes field, + void *val, int len) + { + SFLOWUSAttr *usa = &spec->attr[field]; + if (usa->included) + return false; + usa->included = true; + usa->attr.nla_type = field; + usa->attr.nla_len = sizeof (usa->attr) + len; + int len_w_pad = NLMSG_ALIGN (len); + usa->val.iov_len = len_w_pad; + usa->val.iov_base = val; + spec->n_attrs++; + spec->attrs_len += sizeof (usa->attr); + spec->attrs_len += len_w_pad; + return true; + } + + /*_________________---------------------------__________________ + _________________ SFLOWUSSpec_send __________________ + -----------------___________________________------------------ + */ + + int + SFLOWUSSpec_send (SFLOWUS *ust, SFLOWUSSpec *spec) + { + spec->nlh.nlmsg_len = NLMSG_LENGTH (spec->attrs_len); + spec->nlh.nlmsg_flags = 0; + spec->nlh.nlmsg_seq = ++ust->nl_seq; + spec->nlh.nlmsg_pid = getpid (); + +#define MAX_IOV_FRAGMENTS (2 * __SFLOW_VPP_ATTR_MAX) + 2 + + struct iovec iov[MAX_IOV_FRAGMENTS]; + u32 frag = 0; + iov[frag].iov_base = &spec->nlh; + iov[frag].iov_len = sizeof (spec->nlh); + frag++; + int nn = 0; + for (u32 ii = 0; ii < __SFLOW_VPP_ATTR_MAX; ii++) + { + SFLOWUSAttr *usa = &spec->attr[ii]; + if (usa->included) + { + nn++; + iov[frag].iov_base = &usa->attr; + iov[frag].iov_len = sizeof (usa->attr); + frag++; + iov[frag] = usa->val; // struct copy + frag++; + } + } + ASSERT (nn == spec->n_attrs); + + struct sockaddr_nl da = { + .nl_family = AF_NETLINK, + .nl_groups = (1 << (ust->group_id - 1)) // for multicast to the group + // .nl_pid = 1e9+6343 // for unicast to receiver bound to netlink socket + // with that "pid" + }; + + struct msghdr msg = { .msg_name = &da, + .msg_namelen = sizeof (da), + .msg_iov = iov, + .msg_iovlen = frag }; + + int status = sendmsg (ust->nl_sock, &msg, 0); + if (status <= 0) + { + // Linux replies with ECONNREFUSED when + // a multicast is sent via NETLINK_USERSOCK, but + // it's not an error so we can just ignore it here. + if (errno != ECONNREFUSED) + { + SFLOW_DBG ("USERSOCK strerror(errno) = %s\n", strerror (errno)); + return -1; + } + } + return 0; + } |