svn commit: r344632 - head/sys/netinet

[John Baldwin]

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. */