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268 lines
8.4 KiB
268 lines
8.4 KiB
From 2cf7651f0b1b0123dc5568ebad00ac84a9b3c348 Mon Sep 17 00:00:00 2001
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From: Donald Sharp <sharpd@nvidia.com>
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Date: Wed, 2 Feb 2022 13:28:42 -0500
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Subject: [PATCH] zebra: Make netlink buffer reads resizeable when needed
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Currently when the kernel sends netlink messages to FRR
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the buffers to receive this data is of fixed length.
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The kernel, with certain configurations, will send
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netlink messages that are larger than this fixed length.
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This leads to situations where, on startup, zebra gets
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really confused about the state of the kernel. Effectively
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the current algorithm is this:
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read up to buffer in size
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while (data to parse)
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get netlink message header, look at size
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parse if you can
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The problem is that there is a 32k buffer we read.
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We get the first message that is say 1k in size,
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subtract that 1k to 31k left to parse. We then
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get the next header and notice that the length
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of the message is 33k. Which is obviously larger
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than what we read in. FRR has no recover mechanism
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nor is there a way to know, a priori, what the maximum
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size the kernel will send us.
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Modify FRR to look at the kernel message and see if the
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buffer is large enough, if not, make it large enough to
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read in the message.
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This code has to be per netlink socket because of the usage
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of pthreads. So add to `struct nlsock` the buffer and current
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buffer length. Growing it as necessary.
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Fixes: #10404
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Signed-off-by: Donald Sharp <sharpd@nvidia.com>
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---
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zebra/kernel_netlink.c | 68 +++++++++++++++++++++++++-----------------
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zebra/kernel_netlink.h | 2 +-
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zebra/zebra_dplane.c | 4 +++
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zebra/zebra_ns.h | 3 ++
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4 files changed, 49 insertions(+), 28 deletions(-)
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diff --git a/zebra/kernel_netlink.h b/zebra/kernel_netlink.h
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index ae88f3372b1c..9421ea1c611a 100644
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--- a/zebra/kernel_netlink.h
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+++ b/zebra/kernel_netlink.h
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@@ -96,7 +96,7 @@ extern const char *nl_family_to_str(uint8_t family);
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extern const char *nl_rttype_to_str(uint8_t rttype);
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extern int netlink_parse_info(int (*filter)(struct nlmsghdr *, ns_id_t, int),
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- const struct nlsock *nl,
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+ struct nlsock *nl,
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const struct zebra_dplane_info *dp_info,
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int count, int startup);
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extern int netlink_talk_filter(struct nlmsghdr *h, ns_id_t ns, int startup);
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diff --git a/zebra/zebra_ns.h b/zebra/zebra_ns.h
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index 0519e1d5b33d..7a0ffbc1ee6f 100644
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--- a/zebra/zebra_ns.h
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+++ b/zebra/zebra_ns.h
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@@ -39,6 +39,9 @@ struct nlsock {
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int seq;
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struct sockaddr_nl snl;
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char name[64];
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+
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+ uint8_t *buf;
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+ size_t buflen;
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};
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#endif
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diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c
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index b8eaeb1..14a40a9 100644
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--- a/zebra/kernel_netlink.c
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+++ b/zebra/kernel_netlink.c
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@@ -90,8 +90,6 @@
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*/
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#define NL_DEFAULT_BATCH_SEND_THRESHOLD (15 * NL_PKT_BUF_SIZE)
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-#define NL_BATCH_RX_BUFSIZE NL_RCV_PKT_BUF_SIZE
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-
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static const struct message nlmsg_str[] = {{RTM_NEWROUTE, "RTM_NEWROUTE"},
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{RTM_DELROUTE, "RTM_DELROUTE"},
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{RTM_GETROUTE, "RTM_GETROUTE"},
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@@ -164,8 +162,6 @@ DEFINE_MTYPE_STATIC(ZEBRA, NL_BUF, "Zebra Netlink buffers")
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size_t nl_batch_tx_bufsize;
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char *nl_batch_tx_buf;
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-char nl_batch_rx_buf[NL_BATCH_RX_BUFSIZE];
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-
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_Atomic uint32_t nl_batch_bufsize = NL_DEFAULT_BATCH_BUFSIZE;
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_Atomic uint32_t nl_batch_send_threshold = NL_DEFAULT_BATCH_SEND_THRESHOLD;
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@@ -322,6 +318,9 @@ static int netlink_socket(struct nlsock *nl, unsigned long groups,
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nl->snl = snl;
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nl->sock = sock;
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+ nl->buflen = NL_RCV_PKT_BUF_SIZE;
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+ nl->buf = XMALLOC(MTYPE_NL_BUF, nl->buflen);
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+
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return ret;
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}
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@@ -729,19 +728,29 @@ static ssize_t netlink_send_msg(const struct nlsock *nl, void *buf,
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*
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* Returns -1 on error, 0 if read would block or the number of bytes received.
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*/
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-static int netlink_recv_msg(const struct nlsock *nl, struct msghdr msg,
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- void *buf, size_t buflen)
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+static int netlink_recv_msg(struct nlsock *nl, struct msghdr *msg)
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{
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struct iovec iov;
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int status;
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- iov.iov_base = buf;
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- iov.iov_len = buflen;
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- msg.msg_iov = &iov;
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- msg.msg_iovlen = 1;
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+ iov.iov_base = nl->buf;
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+ iov.iov_len = nl->buflen;
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+ msg->msg_iov = &iov;
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+ msg->msg_iovlen = 1;
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do {
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- status = recvmsg(nl->sock, &msg, 0);
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+ int bytes;
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+
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+ bytes = recv(nl->sock, NULL, 0, MSG_PEEK | MSG_TRUNC);
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+
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+ if (bytes >= 0 && (size_t)bytes > nl->buflen) {
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+ nl->buf = XREALLOC(MTYPE_NL_BUF, nl->buf, bytes);
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+ nl->buflen = bytes;
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+ iov.iov_base = nl->buf;
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+ iov.iov_len = nl->buflen;
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+ }
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+
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+ status = recvmsg(nl->sock, msg, 0);
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} while (status == -1 && errno == EINTR);
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if (status == -1) {
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@@ -761,10 +770,10 @@ static int netlink_recv_msg(const struct nlsock *nl, struct msghdr msg,
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return -1;
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}
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- if (msg.msg_namelen != sizeof(struct sockaddr_nl)) {
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+ if (msg->msg_namelen != sizeof(struct sockaddr_nl)) {
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flog_err(EC_ZEBRA_NETLINK_LENGTH_ERROR,
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"%s sender address length error: length %d", nl->name,
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- msg.msg_namelen);
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+ msg->msg_namelen);
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return -1;
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}
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@@ -873,8 +882,7 @@ static int netlink_parse_error(const struct nlsock *nl, struct nlmsghdr *h,
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* the filter.
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*/
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int netlink_parse_info(int (*filter)(struct nlmsghdr *, ns_id_t, int),
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- const struct nlsock *nl,
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- const struct zebra_dplane_info *zns,
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+ struct nlsock *nl, const struct zebra_dplane_info *zns,
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int count, int startup)
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{
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int status;
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@@ -883,7 +891,6 @@ int netlink_parse_info(int (*filter)(struct nlmsghdr *, ns_id_t, int),
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int read_in = 0;
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while (1) {
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- char buf[NL_RCV_PKT_BUF_SIZE];
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struct sockaddr_nl snl;
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struct msghdr msg = {.msg_name = (void *)&snl,
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.msg_namelen = sizeof(snl)};
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@@ -892,14 +899,14 @@ int netlink_parse_info(int (*filter)(struct nlmsghdr *, ns_id_t, int),
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if (count && read_in >= count)
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return 0;
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- status = netlink_recv_msg(nl, msg, buf, sizeof(buf));
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+ status = netlink_recv_msg(nl, &msg);
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if (status == -1)
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return -1;
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else if (status == 0)
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break;
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read_in++;
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- for (h = (struct nlmsghdr *)buf;
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+ for (h = (struct nlmsghdr *)nl->buf;
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(status >= 0 && NLMSG_OK(h, (unsigned int)status));
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h = NLMSG_NEXT(h, status)) {
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/* Finish of reading. */
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@@ -976,10 +983,10 @@ int netlink_parse_info(int (*filter)(struct nlmsghdr *, ns_id_t, int),
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*/
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static int
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netlink_talk_info(int (*filter)(struct nlmsghdr *, ns_id_t, int startup),
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- struct nlmsghdr *n, const struct zebra_dplane_info *dp_info,
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+ struct nlmsghdr *n, struct zebra_dplane_info *dp_info,
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int startup)
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{
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- const struct nlsock *nl;
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+ struct nlsock *nl;
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nl = &(dp_info->nls);
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n->nlmsg_seq = nl->seq;
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@@ -1067,12 +1074,11 @@ static int nl_batch_read_resp(struct nl_batch *bth)
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* message at a time.
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*/
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while (true) {
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- status = netlink_recv_msg(nl, msg, nl_batch_rx_buf,
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- sizeof(nl_batch_rx_buf));
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+ status = netlink_recv_msg(nl, &msg);
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if (status == -1 || status == 0)
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return status;
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- h = (struct nlmsghdr *)nl_batch_rx_buf;
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+ h = (struct nlmsghdr *)nl->buf;
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ignore_msg = false;
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seq = h->nlmsg_seq;
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/*
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@@ -1506,11 +1512,15 @@ void kernel_terminate(struct zebra_ns *zns, bool complete)
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if (zns->netlink.sock >= 0) {
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close(zns->netlink.sock);
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zns->netlink.sock = -1;
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+ XFREE(MTYPE_NL_BUF, zns->netlink.buf);
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+ zns->netlink.buflen = 0;
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}
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if (zns->netlink_cmd.sock >= 0) {
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close(zns->netlink_cmd.sock);
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zns->netlink_cmd.sock = -1;
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+ XFREE(MTYPE_NL_BUF, zns->netlink_cmd.buf);
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+ zns->netlink_cmd.buflen = 0;
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}
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/* During zebra shutdown, we need to leave the dataplane socket
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@@ -1520,6 +1530,8 @@ void kernel_terminate(struct zebra_ns *zns, bool complete)
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if (zns->netlink_dplane.sock >= 0) {
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close(zns->netlink_dplane.sock);
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zns->netlink_dplane.sock = -1;
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+ XFREE(MTYPE_NL_BUF, zns->netlink_dplane.buf);
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+ zns->netlink_dplane.buflen = 0;
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}
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}
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}
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diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c
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index 14a40a9..2b566d4 100644
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--- a/zebra/kernel_netlink.c
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+++ b/zebra/kernel_netlink.c
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@@ -779,7 +779,7 @@ static int netlink_recv_msg(struct nlsock *nl, struct msghdr *msg)
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if (IS_ZEBRA_DEBUG_KERNEL_MSGDUMP_RECV) {
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zlog_debug("%s: << netlink message dump [recv]", __func__);
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- zlog_hexdump(buf, status);
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+ zlog_hexdump(nl->buf, status);
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}
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return status;
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diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c
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index 2b566d4..0564a6b 100644
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--- a/zebra/kernel_netlink.c
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+++ b/zebra/kernel_netlink.c
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@@ -1060,7 +1060,7 @@ static int nl_batch_read_resp(struct nl_batch *bth)
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struct sockaddr_nl snl;
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struct msghdr msg = {};
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int status, seq;
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- const struct nlsock *nl;
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+ struct nlsock *nl;
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struct zebra_dplane_ctx *ctx;
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bool ignore_msg;
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