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Index: head/share/man/man4/tcp.4
===================================================================
--- head/share/man/man4/tcp.4
+++ head/share/man/man4/tcp.4
@@ -633,7 +633,8 @@
.Xr mod_cc 4 ,
.Xr siftr 4 ,
.Xr syncache 4 ,
-.Xr setkey 8
+.Xr setkey 8 ,
+.Xr tcp_functions 9
.Rs
.%A "V. Jacobson"
.%A "R. Braden"
Index: head/share/man/man9/tcp_functions.9
===================================================================
--- head/share/man/man9/tcp_functions.9
+++ head/share/man/man9/tcp_functions.9
@@ -114,14 +114,17 @@
struct inpcb *inp, struct tcpcb *tp);
/* Optional memory allocation/free routine */
void (*tfb_tcp_fb_init)(struct tcpcb *);
- void (*tfb_tcp_fb_fini)(struct tcpcb *);
+ void (*tfb_tcp_fb_fini)(struct tcpcb *, int);
/* Optional timers, must define all if you define one */
int (*tfb_tcp_timer_stop_all)(struct tcpcb *);
void (*tfb_tcp_timer_activate)(struct tcpcb *,
uint32_t, u_int);
int (*tfb_tcp_timer_active)(struct tcpcb *, uint32_t);
void (*tfb_tcp_timer_stop)(struct tcpcb *, uint32_t);
+ /* Optional functions */
void (*tfb_tcp_rexmit_tmr)(struct tcpcb *);
+ void (*tfb_tcp_handoff_ok)(struct tcpcb *);
+ /* System use */
volatile uint32_t tfb_refcnt;
uint32_t tfb_flags;
};
@@ -157,6 +160,16 @@
.Va tfb_tcp_fb_fini
field.
.Pp
+If the
+.Va tfb_tcp_fb_fini
+argument is non-NULL, the function to which it points is called when the
+kernel is destroying the TCP control block or when the socket is transitioning
+to use a different TCP stack.
+The function is called with arguments of the TCP control block and an integer
+flag.
+The flag will be zero if the socket is transitioning to use another TCP stack
+or one if the TCP control block is being destroyed.
+.Pp
If the TCP stack implements additional timers, the TCP stack should set a
non-NULL pointer in the
.Va tfb_tcp_timer_stop_all ,
@@ -193,6 +206,37 @@
TCP control block in a valid state for the remainder of the retransmit
timer logic.
.Pp
+A user may select a new TCP stack before calling
+.Xr connect 2
+or
+.Xr listen 2 .
+Optionally, a TCP stack may also allow a user to begin using the TCP stack for
+a connection that is in a later state by setting a non-NULL function pointer in
+the
+.Va tfb_tcp_handoff_ok
+field.
+If this field is non-NULL and a user attempts to select that TCP stack after
+calling
+.Xr connect 2
+or
+.Xr listen 2
+for that socket, the kernel will call the function pointed to by the
+.Va tfb_tcp_handoff_ok
+field.
+The function should return 0 if the user is allowed to switch the socket to use
+the TCP stack. Otherwise, the function should return an error code, which will
+be returned to the user.
+If the
+.Va tfb_tcp_handoff_ok
+field is
+.Dv NULL
+and a user attempts to select the TCP stack after calling
+.Xr connect 2
+or
+.Xr listen 2
+for that socket, the operation will fail and the kernel will return
+.Er EINVAL .
+.Pp
The
.Va tfb_refcnt
and
@@ -269,8 +313,10 @@
.Fa blk
argument references a function block that is not currently registered.
.Sh SEE ALSO
-.Xr malloc 9 ,
-.Xr tcp 4
+.Xr connect 2 ,
+.Xr listen 2 ,
+.Xr tcp 4 ,
+.Xr malloc 9
.Sh HISTORY
This framework first appeared in
.Fx 11.0 .
Index: head/sys/netinet/tcp_subr.c
===================================================================
--- head/sys/netinet/tcp_subr.c
+++ head/sys/netinet/tcp_subr.c
@@ -1187,9 +1187,6 @@
tp->t_fb = tcp_func_set_ptr;
refcount_acquire(&tp->t_fb->tfb_refcnt);
rw_runlock(&tcp_function_lock);
- if (tp->t_fb->tfb_tcp_fb_init) {
- (*tp->t_fb->tfb_tcp_fb_init)(tp);
- }
/*
* Use the current system default CC algorithm.
*/
@@ -1201,7 +1198,7 @@
if (CC_ALGO(tp)->cb_init != NULL)
if (CC_ALGO(tp)->cb_init(tp->ccv) > 0) {
if (tp->t_fb->tfb_tcp_fb_fini)
- (*tp->t_fb->tfb_tcp_fb_fini)(tp);
+ (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
refcount_release(&tp->t_fb->tfb_refcnt);
uma_zfree(V_tcpcb_zone, tm);
return (NULL);
@@ -1210,7 +1207,7 @@
tp->osd = &tm->osd;
if (khelp_init_osd(HELPER_CLASS_TCP, tp->osd)) {
if (tp->t_fb->tfb_tcp_fb_fini)
- (*tp->t_fb->tfb_tcp_fb_fini)(tp);
+ (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
refcount_release(&tp->t_fb->tfb_refcnt);
uma_zfree(V_tcpcb_zone, tm);
return (NULL);
@@ -1271,6 +1268,9 @@
*/
tcp_pcap_tcpcb_init(tp);
#endif
+ if (tp->t_fb->tfb_tcp_fb_init) {
+ (*tp->t_fb->tfb_tcp_fb_init)(tp);
+ }
return (tp); /* XXX */
}
@@ -1484,7 +1484,7 @@
if (tp->t_timers->tt_draincnt == 0) {
/* We own the last reference on tcpcb, let's free it. */
if (tp->t_fb->tfb_tcp_fb_fini)
- (*tp->t_fb->tfb_tcp_fb_fini)(tp);
+ (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
refcount_release(&tp->t_fb->tfb_refcnt);
tp->t_inpcb = NULL;
uma_zfree(V_tcpcb_zone, tp);
@@ -1513,7 +1513,7 @@
if (tp->t_timers->tt_draincnt == 0) {
/* We own the last reference on this tcpcb, let's free it. */
if (tp->t_fb->tfb_tcp_fb_fini)
- (*tp->t_fb->tfb_tcp_fb_fini)(tp);
+ (*tp->t_fb->tfb_tcp_fb_fini)(tp, 1);
refcount_release(&tp->t_fb->tfb_refcnt);
tp->t_inpcb = NULL;
uma_zfree(V_tcpcb_zone, tp);
Index: head/sys/netinet/tcp_syncache.c
===================================================================
--- head/sys/netinet/tcp_syncache.c
+++ head/sys/netinet/tcp_syncache.c
@@ -842,7 +842,7 @@
KASSERT(rblk != NULL,
("cannot find blk %p out of syncache?", blk));
if (tp->t_fb->tfb_tcp_fb_fini)
- (*tp->t_fb->tfb_tcp_fb_fini)(tp);
+ (*tp->t_fb->tfb_tcp_fb_fini)(tp, 0);
refcount_release(&tp->t_fb->tfb_refcnt);
tp->t_fb = rblk;
if (tp->t_fb->tfb_tcp_fb_init) {
Index: head/sys/netinet/tcp_usrreq.c
===================================================================
--- head/sys/netinet/tcp_usrreq.c
+++ head/sys/netinet/tcp_usrreq.c
@@ -1420,40 +1420,59 @@
if (error)
return (error);
INP_WLOCK_RECHECK(inp);
- if (tp->t_state != TCPS_CLOSED) {
- /*
- * The user has advanced the state
- * past the initial point, we can't
- * switch since we are down the road
- * and a new set of functions may
- * not be compatibile.
- */
- INP_WUNLOCK(inp);
- return(EINVAL);
- }
blk = find_and_ref_tcp_functions(&fsn);
if (blk == NULL) {
INP_WUNLOCK(inp);
return (ENOENT);
}
- if (tp->t_fb != blk) {
- if (blk->tfb_flags & TCP_FUNC_BEING_REMOVED) {
+ if (tp->t_fb == blk) {
+ /* You already have this */
+ refcount_release(&blk->tfb_refcnt);
+ INP_WUNLOCK(inp);
+ return (0);
+ }
+ if (tp->t_state != TCPS_CLOSED) {
+ int error=EINVAL;
+ /*
+ * The user has advanced the state
+ * past the initial point, we may not
+ * be able to switch.
+ */
+ if (blk->tfb_tcp_handoff_ok != NULL) {
+ /*
+ * Does the stack provide a
+ * query mechanism, if so it may
+ * still be possible?
+ */
+ error = (*blk->tfb_tcp_handoff_ok)(tp);
+ }
+ if (error) {
refcount_release(&blk->tfb_refcnt);
INP_WUNLOCK(inp);
- return (ENOENT);
+ return(error);
}
+ }
+ if (blk->tfb_flags & TCP_FUNC_BEING_REMOVED) {
+ refcount_release(&blk->tfb_refcnt);
+ INP_WUNLOCK(inp);
+ return (ENOENT);
+ }
+ /*
+ * Release the old refcnt, the
+ * lookup acquired a ref on the
+ * new one already.
+ */
+ if (tp->t_fb->tfb_tcp_fb_fini) {
/*
- * Release the old refcnt, the
- * lookup acquires a ref on the
- * new one.
+ * Tell the stack to cleanup with 0 i.e.
+ * the tcb is not going away.
*/
- if (tp->t_fb->tfb_tcp_fb_fini)
- (*tp->t_fb->tfb_tcp_fb_fini)(tp);
- refcount_release(&tp->t_fb->tfb_refcnt);
- tp->t_fb = blk;
- if (tp->t_fb->tfb_tcp_fb_init) {
- (*tp->t_fb->tfb_tcp_fb_init)(tp);
- }
+ (*tp->t_fb->tfb_tcp_fb_fini)(tp, 0);
+ }
+ refcount_release(&tp->t_fb->tfb_refcnt);
+ tp->t_fb = blk;
+ if (tp->t_fb->tfb_tcp_fb_init) {
+ (*tp->t_fb->tfb_tcp_fb_init)(tp);
}
#ifdef TCP_OFFLOAD
if (tp->t_flags & TF_TOE) {
Index: head/sys/netinet/tcp_var.h
===================================================================
--- head/sys/netinet/tcp_var.h
+++ head/sys/netinet/tcp_var.h
@@ -116,6 +116,18 @@
* does not know your callbacks you must provide a
* stop_all function that loops through and calls
* tcp_timer_stop() with each of your defined timers.
+ * Adding a tfb_tcp_handoff_ok function allows the socket
+ * option to change stacks to query you even if the
+ * connection is in a later stage. You return 0 to
+ * say you can take over and run your stack, you return
+ * non-zero (an error number) to say no you can't.
+ * If the function is undefined you can only change
+ * in the early states (before connect or listen).
+ * tfb_tcp_fb_fini is changed to add a flag to tell
+ * the old stack if the tcb is being destroyed or
+ * not. A one in the flag means the TCB is being
+ * destroyed, a zero indicates its transitioning to
+ * another stack (via socket option).
*/
struct tcp_function_block {
char tfb_tcp_block_name[TCP_FUNCTION_NAME_LEN_MAX];
@@ -128,7 +140,7 @@
struct inpcb *inp, struct tcpcb *tp);
/* Optional memory allocation/free routine */
void (*tfb_tcp_fb_init)(struct tcpcb *);
- void (*tfb_tcp_fb_fini)(struct tcpcb *);
+ void (*tfb_tcp_fb_fini)(struct tcpcb *, int);
/* Optional timers, must define all if you define one */
int (*tfb_tcp_timer_stop_all)(struct tcpcb *);
void (*tfb_tcp_timer_activate)(struct tcpcb *,
@@ -136,6 +148,7 @@
int (*tfb_tcp_timer_active)(struct tcpcb *, uint32_t);
void (*tfb_tcp_timer_stop)(struct tcpcb *, uint32_t);
void (*tfb_tcp_rexmit_tmr)(struct tcpcb *);
+ int (*tfb_tcp_handoff_ok)(struct tcpcb *);
volatile uint32_t tfb_refcnt;
uint32_t tfb_flags;
};

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