git: 8f5a0a2e4f31 - main - sockets: provide solisten_clone(), solisten_enqueue()
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Date: Wed, 10 Aug 2022 18:10:27 UTC
The branch main has been updated by glebius:
URL: https://cgit.FreeBSD.org/src/commit/?id=8f5a0a2e4f315a03caaa2d51efdcf837e303e510
commit 8f5a0a2e4f315a03caaa2d51efdcf837e303e510
Author: Gleb Smirnoff <glebius@FreeBSD.org>
AuthorDate: 2022-08-10 18:09:34 +0000
Commit: Gleb Smirnoff <glebius@FreeBSD.org>
CommitDate: 2022-08-10 18:09:34 +0000
sockets: provide solisten_clone(), solisten_enqueue()
as alternative KPI to sonewconn(). The latter has three stages:
- check the listening socket queue limits
- allocate a new socket
- call into protocol attach method
- link the new socket into the listen queue of the listening socket
The attach method, originally designed for a creation of socket by the
socket(2) syscall has slightly different semantics than attach of a socket
cloned by listener. Make it possible for protocols to call into the
first stage, then perform a different attach, and then call into the
final stage. The first stage, that checks limits and clones a socket
is called solisten_clone(), and the function that enqueues the socket
is solisten_enqueue().
Reviewed by: tuexen
Differential revision: https://reviews.freebsd.org/D36063
---
sys/kern/uipc_socket.c | 86 +++++++++++++++++++++++++++++++++++---------------
sys/sys/socketvar.h | 3 ++
2 files changed, 64 insertions(+), 25 deletions(-)
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index 8ecf83d30e28..73725efceb2d 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -587,16 +587,17 @@ SYSCTL_TIMEVAL_SEC(_kern_ipc, OID_AUTO, sooverinterval, CTLFLAG_RW,
"Delay in seconds between warnings for listen socket overflows");
/*
- * When an attempt at a new connection is noted on a socket which accepts
- * connections, sonewconn is called. If the connection is possible (subject
- * to space constraints, etc.) then we allocate a new structure, properly
- * linked into the data structure of the original socket, and return this.
- * Connstatus may be 0, or SS_ISCONFIRMING, or SS_ISCONNECTED.
+ * When an attempt at a new connection is noted on a socket which supports
+ * accept(2), the protocol has two options:
+ * 1) Call legacy sonewconn() function, which would call protocol attach
+ * method, same as used for socket(2).
+ * 2) Call solisten_clone(), do attach that is specific to a cloned connection,
+ * and then call solisten_enqueue().
*
* Note: the ref count on the socket is 0 on return.
*/
struct socket *
-sonewconn(struct socket *head, int connstatus)
+solisten_clone(struct socket *head)
{
struct sbuf descrsb;
struct socket *so;
@@ -701,20 +702,27 @@ sonewconn(struct socket *head, int connstatus)
}
KASSERT(sbuf_len(&descrsb) > 0,
("%s: sbuf creation failed", __func__));
+ /*
+ * Preserve the historic listen queue overflow log
+ * message, that starts with "sonewconn:". It has
+ * been known to sysadmins for years and also test
+ * sys/kern/sonewconn_overflow checks for it.
+ */
if (head->so_cred == 0) {
- log(LOG_DEBUG,
- "%s: pcb %p (%s): Listen queue overflow: "
- "%i already in queue awaiting acceptance "
- "(%d occurrences)\n",
- __func__, head->so_pcb, sbuf_data(&descrsb),
+ log(LOG_DEBUG, "sonewconn: pcb %p (%s): "
+ "Listen queue overflow: %i already in "
+ "queue awaiting acceptance (%d "
+ "occurrences)\n", head->so_pcb,
+ sbuf_data(&descrsb),
qlen, overcount);
} else {
- log(LOG_DEBUG, "%s: pcb %p (%s): Listen queue overflow: "
+ log(LOG_DEBUG, "sonewconn: pcb %p (%s): "
+ "Listen queue overflow: "
"%i already in queue awaiting acceptance "
"(%d occurrences), euid %d, rgid %d, jail %s\n",
- __func__, head->so_pcb, sbuf_data(&descrsb),
- qlen, overcount,
- head->so_cred->cr_uid, head->so_cred->cr_rgid,
+ head->so_pcb, sbuf_data(&descrsb), qlen,
+ overcount, head->so_cred->cr_uid,
+ head->so_cred->cr_rgid,
head->so_cred->cr_prison ?
head->so_cred->cr_prison->pr_name :
"not_jailed");
@@ -758,25 +766,52 @@ sonewconn(struct socket *head, int connstatus)
__func__, head->so_pcb);
return (NULL);
}
+ so->so_rcv.sb_lowat = head->sol_sbrcv_lowat;
+ so->so_snd.sb_lowat = head->sol_sbsnd_lowat;
+ so->so_rcv.sb_timeo = head->sol_sbrcv_timeo;
+ so->so_snd.sb_timeo = head->sol_sbsnd_timeo;
+ so->so_rcv.sb_flags = head->sol_sbrcv_flags & SB_AUTOSIZE;
+ so->so_snd.sb_flags = head->sol_sbsnd_flags & SB_AUTOSIZE;
if ((so->so_proto->pr_flags & PR_SOCKBUF) == 0) {
so->so_snd.sb_mtx = &so->so_snd_mtx;
so->so_rcv.sb_mtx = &so->so_rcv_mtx;
}
- /* Socket starts with a reference from the listen queue. */
- refcount_init(&so->so_count, 1);
+
+ return (so);
+}
+
+/* Connstatus may be 0, or SS_ISCONFIRMING, or SS_ISCONNECTED. */
+struct socket *
+sonewconn(struct socket *head, int connstatus)
+{
+ struct socket *so;
+
+ if ((so = solisten_clone(head)) == NULL)
+ return (NULL);
+
if ((*so->so_proto->pr_usrreqs->pru_attach)(so, 0, NULL)) {
- MPASS(refcount_release(&so->so_count));
sodealloc(so);
log(LOG_DEBUG, "%s: pcb %p: pru_attach() failed\n",
__func__, head->so_pcb);
return (NULL);
}
- so->so_rcv.sb_lowat = head->sol_sbrcv_lowat;
- so->so_snd.sb_lowat = head->sol_sbsnd_lowat;
- so->so_rcv.sb_timeo = head->sol_sbrcv_timeo;
- so->so_snd.sb_timeo = head->sol_sbsnd_timeo;
- so->so_rcv.sb_flags |= head->sol_sbrcv_flags & SB_AUTOSIZE;
- so->so_snd.sb_flags |= head->sol_sbsnd_flags & SB_AUTOSIZE;
+
+ solisten_enqueue(so, connstatus);
+
+ return (so);
+}
+
+/*
+ * Enqueue socket cloned by solisten_clone() to the listen queue of the
+ * listener it has been cloned from.
+ */
+void
+solisten_enqueue(struct socket *so, int connstatus)
+{
+ struct socket *head = so->so_listen;
+
+ MPASS(refcount_load(&so->so_count) == 0);
+ refcount_init(&so->so_count, 1);
SOLISTEN_LOCK(head);
if (head->sol_accept_filter != NULL)
@@ -815,13 +850,14 @@ sonewconn(struct socket *head, int connstatus)
head->sol_incqlen++;
SOLISTEN_UNLOCK(head);
}
- return (so);
}
#if defined(SCTP) || defined(SCTP_SUPPORT)
/*
* Socket part of sctp_peeloff(). Detach a new socket from an
* association. The new socket is returned with a reference.
+ *
+ * XXXGL: reduce copy-paste with solisten_clone().
*/
struct socket *
sopeeloff(struct socket *head)
diff --git a/sys/sys/socketvar.h b/sys/sys/socketvar.h
index c496239f92bc..ed797c6d6239 100644
--- a/sys/sys/socketvar.h
+++ b/sys/sys/socketvar.h
@@ -474,7 +474,10 @@ int solisten(struct socket *so, int backlog, struct thread *td);
void solisten_proto(struct socket *so, int backlog);
void solisten_proto_abort(struct socket *so);
int solisten_proto_check(struct socket *so);
+void solisten_enqueue(struct socket *, int);
int solisten_dequeue(struct socket *, struct socket **, int);
+struct socket *
+ solisten_clone(struct socket *);
struct socket *
sonewconn(struct socket *head, int connstatus);
struct socket *