[PATCH 32/33] net: add a new bind_add method

Christoph Hellwig
2020-05-20T19:57:18Z

The SCTP protocol allows to bind multiple address to a socket. That
feature is currently only exposed as a socket option. Add a bind_add
method struct proto that allows to bind additional addresses, and
switch the dlm code to use the method instead of going through the
socket option from kernel space.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/dlm/lowcomms.c | 9 +++------
include/net/sock.h | 6 +++++-
net/core/sock.c | 8 ++++++++
net/sctp/socket.c | 23 +++++++++++++++++++++++
4 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 9f1c3cdc9d653..3543a8fec9075 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -882,6 +882,7 @@ static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
static int sctp_bind_addrs(struct connection *con, uint16_t port)
{
struct sockaddr_storage localaddr;
+ struct sockaddr *addr = (struct sockaddr *)&localaddr;
int i, addr_len, result = 0;

for (i = 0; i < dlm_local_count; i++) {
@@ -889,13 +890,9 @@ static int sctp_bind_addrs(struct connection *con, uint16_t port)
make_sockaddr(&localaddr, port, &addr_len);

if (!i)
- result = kernel_bind(con->sock,
- (struct sockaddr *)&localaddr,
- addr_len);
+ result = kernel_bind(con->sock, addr, addr_len);
else
- result = kernel_setsockopt(con->sock, SOL_SCTP,
- SCTP_SOCKOPT_BINDX_ADD,
- (char *)&localaddr, addr_len);
+ result = sock_bind_add(con->sock->sk, addr, addr_len);

if (result < 0) {
log_print("Can't bind to %d addr number %d, %d.\n",
diff --git a/include/net/sock.h b/include/net/sock.h
index d994daa418ec2..6e9f713a78607 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1156,7 +1156,9 @@ struct proto {
int (*sendpage)(struct sock *sk, struct page *page,
int offset, size_t size, int flags);
int (*bind)(struct sock *sk,
- struct sockaddr *uaddr, int addr_len);
+ struct sockaddr *addr, int addr_len);
+ int (*bind_add)(struct sock *sk,
+ struct sockaddr *addr, int addr_len);

int (*backlog_rcv) (struct sock *sk,
struct sk_buff *skb);
@@ -2698,4 +2700,6 @@ void sock_set_reuseaddr(struct sock *sk);
void sock_set_reuseport(struct sock *sk);
void sock_set_sndtimeo(struct sock *sk, s64 secs);

+int sock_bind_add(struct sock *sk, struct sockaddr *addr, int addr_len);
+
#endif /* _SOCK_H */
diff --git a/net/core/sock.c b/net/core/sock.c
index 2ca3425b519c0..61ec573221a60 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3712,3 +3712,11 @@ bool sk_busy_loop_end(void *p, unsigned long start_time)
}
EXPORT_SYMBOL(sk_busy_loop_end);
#endif /* CONFIG_NET_RX_BUSY_POLL */
+
+int sock_bind_add(struct sock *sk, struct sockaddr *addr, int addr_len)
+{
+ if (!sk->sk_prot->bind_add)
+ return -EOPNOTSUPP;
+ return sk->sk_prot->bind_add(sk, addr, addr_len);
+}
+EXPORT_SYMBOL(sock_bind_add);
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 827a9903ee288..8a0b9258f65c0 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1057,6 +1057,27 @@ static int sctp_setsockopt_bindx(struct sock *sk,
return err;
}

+static int sctp_bind_add(struct sock *sk, struct sockaddr *addr,
+ int addrlen)
+{
+ struct sctp_af *af = sctp_get_af_specific(addr->sa_family);
+ int err;
+
+ if (!af || af->sockaddr_len > addrlen)
+ return -EINVAL;
+ err = security_sctp_bind_connect(sk, SCTP_SOCKOPT_BINDX_ADD, addr,
+ addrlen);
+ if (err)
+ return err;
+
+ lock_sock(sk);
+ err = sctp_do_bind(sk, (union sctp_addr *)addr, af->sockaddr_len);
+ if (!err)
+ err = sctp_send_asconf_add_ip(sk, addr, 1);
+ release_sock(sk);
+ return err;
+}
+
static int sctp_connect_new_asoc(struct sctp_endpoint *ep,
const union sctp_addr *daddr,
const struct sctp_initmsg *init,
@@ -9625,6 +9646,7 @@ struct proto sctp_prot = {
.sendmsg = sctp_sendmsg,
.recvmsg = sctp_recvmsg,
.bind = sctp_bind,
+ .bind_add = sctp_bind_add,
.backlog_rcv = sctp_backlog_rcv,
.hash = sctp_hash,
.unhash = sctp_unhash,
@@ -9667,6 +9689,7 @@ struct proto sctpv6_prot = {
.sendmsg = sctp_sendmsg,
.recvmsg = sctp_recvmsg,
.bind = sctp_bind,
+ .bind_add = sctp_bind_add,
.backlog_rcv = sctp_backlog_rcv,
.hash = sctp_hash,
.unhash = sctp_unhash,
--
2.26.2