Author: jhb
Date: Wed Feb 27 20:24:23 2019
New Revision: 344632
URL: https://svnweb.freebsd.org/changeset/base/344632
Log:
Various cleanups to the management of multiple TCP stacks.
- Use strlcpy() with sizeof() instead of strncpy().
- Simplify initialization of TCP functions structures.
init_tcp_functions() was already called before the first call to
register a stack. Just inline the work in the SYSINIT and remove
the racy helper variable. Instead, KASSERT that the rw lock is
initialized when registering a stack.
- Protect the default stack via a direct pointer comparison.
The default stack uses the name "freebsd" instead of "default" so
this protection wasn't working for the default stack anyway.
Reviewed by: rrs
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D19152
Modified:
head/sys/netinet/tcp_subr.c
Modified: head/sys/netinet/tcp_subr.c
==============================================================================
--- head/sys/netinet/tcp_subr.c Wed Feb 27 20:09:58 2019 (r344631)
+++ head/sys/netinet/tcp_subr.c Wed Feb 27 20:24:23 2019 (r344632)
@@ -257,21 +257,10 @@ static struct tcp_function_block tcp_def_funcblk = {
.tfb_tcp_fb_fini = tcp_default_fb_fini,
};
-int t_functions_inited = 0;
static int tcp_fb_cnt = 0;
struct tcp_funchead t_functions;
static struct tcp_function_block *tcp_func_set_ptr = &tcp_def_funcblk;
-static void
-init_tcp_functions(void)
-{
- if (t_functions_inited == 0) {
- TAILQ_INIT(&t_functions);
- rw_init_flags(&tcp_function_lock, "tcp_func_lock" , 0);
- t_functions_inited = 1;
- }
-}
-
static struct tcp_function_block *
find_tcp_functions_locked(struct tcp_function_set *fs)
{
@@ -559,13 +548,10 @@ sysctl_net_inet_list_func_info(SYSCTL_HANDLER_ARGS)
bzero(&tfi, sizeof(tfi));
tfi.tfi_refcnt = f->tf_fb->tfb_refcnt;
tfi.tfi_id = f->tf_fb->tfb_id;
- (void)strncpy(tfi.tfi_alias, f->tf_name,
- TCP_FUNCTION_NAME_LEN_MAX);
- tfi.tfi_alias[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
- (void)strncpy(tfi.tfi_name,
- f->tf_fb->tfb_tcp_block_name,
- TCP_FUNCTION_NAME_LEN_MAX);
- tfi.tfi_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
+ (void)strlcpy(tfi.tfi_alias, f->tf_name,
+ sizeof(tfi.tfi_alias));
+ (void)strlcpy(tfi.tfi_name,
+ f->tf_fb->tfb_tcp_block_name, sizeof(tfi.tfi_name));
error = SYSCTL_OUT(req, &tfi, sizeof(tfi));
/*
* Don't stop on error, as that is the
@@ -781,10 +767,9 @@ register_tcp_functions_as_names(struct tcp_function_bl
KASSERT(names != NULL && *num_names > 0,
("%s: Called with 0-length name list", __func__));
KASSERT(names != NULL, ("%s: Called with NULL name list", __func__));
+ KASSERT(rw_initialized(&tcp_function_lock),
+ ("%s: called too early", __func__));
- if (t_functions_inited == 0) {
- init_tcp_functions();
- }
if ((blk->tfb_tcp_output == NULL) ||
(blk->tfb_tcp_do_segment == NULL) ||
(blk->tfb_tcp_ctloutput == NULL) ||
@@ -824,9 +809,8 @@ register_tcp_functions_as_names(struct tcp_function_bl
}
n->tf_fb = blk;
- (void)strncpy(fs.function_set_name, names[i],
- TCP_FUNCTION_NAME_LEN_MAX);
- fs.function_set_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
+ (void)strlcpy(fs.function_set_name, names[i],
+ sizeof(fs.function_set_name));
rw_wlock(&tcp_function_lock);
if (find_tcp_functions_locked(&fs) != NULL) {
/* Duplicate name space not allowed */
@@ -835,8 +819,7 @@ register_tcp_functions_as_names(struct tcp_function_bl
error = EALREADY;
goto cleanup;
}
- (void)strncpy(n->tf_name, names[i], TCP_FUNCTION_NAME_LEN_MAX);
- n->tf_name[TCP_FUNCTION_NAME_LEN_MAX - 1] = '\0';
+ (void)strlcpy(n->tf_name, names[i], sizeof(n->tf_name));
TAILQ_INSERT_TAIL(&t_functions, n, tf_next);
tcp_fb_cnt++;
rw_wunlock(&tcp_function_lock);
@@ -923,8 +906,8 @@ deregister_tcp_functions(struct tcp_function_block *bl
bool force)
{
struct tcp_function *f;
-
- if (strcmp(blk->tfb_tcp_block_name, "default") == 0) {
+
+ if (blk == &tcp_def_funcblk) {
/* You can't un-register the default */
return (EPERM);
}
@@ -1090,8 +1073,10 @@ tcp_init(void)
tcp_rexmit_slop = TCPTV_CPU_VAR;
tcp_finwait2_timeout = TCPTV_FINWAIT2_TIMEOUT;
tcp_tcbhashsize = hashsize;
+
/* Setup the tcp function block list */
- init_tcp_functions();
+ TAILQ_INIT(&t_functions);
+ rw_init(&tcp_function_lock, "tcp_func_lock");
register_tcp_functions(&tcp_def_funcblk, M_WAITOK);
#ifdef TCP_BLACKBOX
/* Initialize the TCP logging data. */
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