[PATCH v8 15/19] pesto: Parse and add new rules from command line

[Stefano Brivio <sbrivio@redhat.com>]

From: David Gibson <david@gibson.dropbear.id.au>

This adds parsing of options using fwd_rule_parse(), validates them and
adds them to the existing rules. It doesn't yet send those rules back to
passt or pasta.

Message-ID: <20260322141843.4095972-3-sbrivio@redhat.com>
[dwg: Based on an early draft by Stefano]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Recycled usage messages for -T and -U from conf.c as
 suggested by Laurent, dropped unrelated whitespace change]
[sbrivio: Add description of -t, -u, -T, -U to pesto.1]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
---
 Makefile   |   1 +
 fwd_rule.c |   2 +-
 fwd_rule.h |   1 +
 pesto.1    | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 pesto.c    | 111 ++++++++++++++++++++++++++++++++++++++++++++--
 5 files changed, 237 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 9e99dd1..c746b55 100644
--- a/Makefile
+++ b/Makefile
@@ -226,6 +226,7 @@ cppcheck: passt.cppcheck passt-repair.cppcheck pesto.cppcheck qrap.cppcheck
 passt.cppcheck: BASE_CPPFLAGS += -UPESTO
 passt.cppcheck: CPPCHECK_FLAGS += \
 	--suppress=unusedFunction:fwd_rule.c \
+	--suppress=staticFunction:fwd_rule.c \
 	--suppress=unusedFunction:serialise.c
 passt.cppcheck: $(PASST_SRCS) $(PASST_HEADERS) seccomp.h
 
diff --git a/fwd_rule.c b/fwd_rule.c
index c2824d5..b55e4df 100644
--- a/fwd_rule.c
+++ b/fwd_rule.c
@@ -187,7 +187,7 @@ static bool fwd_rule_conflicts(const struct fwd_rule *a, const struct fwd_rule *
  *
  * Return: 0 on success, negative error code on failure
  */
-static int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new)
+int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new)
 {
 	/* Flags which can be set from the caller */
 	const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN | FWD_DUAL_STACK_ANY;
diff --git a/fwd_rule.h b/fwd_rule.h
index 330d49e..f43b37d 100644
--- a/fwd_rule.h
+++ b/fwd_rule.h
@@ -103,6 +103,7 @@ const char *fwd_rule_fmt(const struct fwd_rule *rule, char *dst, size_t size);
 void fwd_rule_parse(char optname, const char *optarg, struct fwd_table *fwd);
 int fwd_rule_read(int fd, struct fwd_rule *rule);
 int fwd_rule_write(int fd, const struct fwd_rule *rule);
+int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new);
 
 /**
  * fwd_rules_dump() - Dump forwarding rules
diff --git a/pesto.1 b/pesto.1
index b06433d..1ea1d12 100644
--- a/pesto.1
+++ b/pesto.1
@@ -31,6 +31,133 @@ Be verbose.
 .BR \-h ", " \-\-help
 Display a help message and exit.
 
+.TP
+.BR \-t ", " \-\-tcp-ports " " \fIspec
+Configure TCP port forwarding to guest or namespace. \fIspec\fR can be one of:
+.RS
+
+.TP
+.BR none
+Don't forward any ports
+
+.TP
+[\fIaddress\fR[\fB%\fR\fIinterface\fR]\fB/\fR]\fIports\fR ...
+Specific ports to forward.  Optionally, a specific listening address
+and interface name (since Linux 5.7) can be specified.  \fIports\fR
+may be either:
+.RS
+.TP
+\fBall\fR
+Forward all unbound, non-ephemeral ports, as permitted by current capabilities.
+No failures are reported for unavailable ports, unless no ports could be
+forwarded at all.
+.RE
+
+.RS
+or a comma-separated list of entries which may be any of:
+.TP
+\fIfirst\fR[\fB-\fR\fIlast\fR][\fB:\fR\fItofirst\fR[\fB-\fR\fItolast\fR]]
+Include range. Forward port numbers between \fIfirst\fR and \fIlast\fR
+(inclusive) to ports between \fItofirst\fR and \fItolast\fR.  If
+\fItofirst\fR and \fItolast\fR are omitted, assume the same as
+\fIfirst\fR and \fIlast\fR.  If \fIlast\fR is omitted, assume the same
+as \fIfirst\fR.
+
+.TP
+\fB~\fR\fIfirst\fR[\fB-\fR\fIlast\fR]
+Exclude range.  Don't forward port numbers between \fIfirst\fR and
+\fIlast\fR.  This takes precedences over include ranges.
+
+.TP
+.BR auto
+\fBpasta\fR only.  Only forward ports in the specified set if the
+target ports are bound in the namespace. The list of ports is
+periodically derived (every second) from listening sockets reported by
+\fI/proc/net/tcp\fR and \fI/proc/net/tcp6\fR, see \fBproc\fR(5).
+.RE
+
+Specifying excluded ranges only implies that all other non-ephemeral
+ports are forwarded. Specifying no ranges at all implies forwarding
+all non-ephemeral ports permitted by current capabilities.  In this
+case, no failures are reported for unavailable ports, unless no ports
+could be forwarded at all.
+
+Examples:
+.RS
+.TP
+-t all
+Forward all unbound, non-ephemeral ports as permitted by current
+capabilities to the corresponding port on the guest or namespace
+.TP
+-t ::1/all
+For the local address ::1, forward all unbound, non-ephemeral ports as
+permitted by current capabilities
+.TP
+-t 22
+Forward local port 22 to port 22 on the guest or namespace
+.TP
+-t 22:23
+Forward local port 22 to port 23 on the guest or namespace
+.TP
+-t 22,25
+Forward local ports 22 and 25 to ports 22 and 25 on the guest or namespace
+.TP
+-t 22-80
+Forward local ports between 22 and 80 to corresponding ports on the guest or
+namespace
+.TP
+-t 22-80:32-90
+Forward local ports between 22 and 80 to ports between 32 and 90 on the guest or
+namespace
+.TP
+-t 192.0.2.1/22
+Forward local port 22, bound to 192.0.2.1, to port 22 on the guest or namespace
+.TP
+-t 192.0.2.1%eth0/22
+Forward local port 22, bound to 192.0.2.1 and interface eth0, to port 22
+.TP
+-t %eth0/22
+Forward local port 22, bound to any address on interface eth0, to port 22
+.TP
+-t 2000-5000,~3000-3010
+Forward local ports between 2000 and 5000, except for those between 3000 and
+3010
+.TP
+-t 192.0.2.1/20-30,~25
+For the local address 192.0.2.1, forward ports between 20 and 24 and between 26
+and 30
+.TP
+-t ~20000-20010
+Forward all ports to the guest, except for the range from 20000 to 20010
+.TP
+-t auto
+Automatically forward any ports which are bound in the namespace
+.TP
+-t ::1/auto
+Automatically forward any ports which are bound in the namespace,
+listening only on local port ::1
+.TP
+-t 8000-8010,auto
+Forward ports in the range 8000-8010 if and only if they are bound in
+the namespace
+.RE
+.RE
+
+.TP
+.BR \-u ", " \-\-udp-ports " " \fIspec
+Configure UDP port forwarding to guest. \fIspec\fR is as described for TCP
+above.
+
+.TP
+.BR \-T ", " \-\-tcp-ns " " \fIspec
+Configure TCP port forwarding from target namespace to init namespace.
+\fIspec\fR is as described above.
+
+.TP
+.BR \-U ", " \-\-udp-ns " " \fIspec
+Configure UDP port forwarding from target namespace to init namespace.
+\fIspec\fR is as described above.
+
 .TP
 .BR \-\-version
 Show version and exit.
diff --git a/pesto.c b/pesto.c
index 92a8cb2..16b3a5a 100644
--- a/pesto.c
+++ b/pesto.c
@@ -55,6 +55,43 @@ static void usage(const char *name, FILE *f, int status)
 	FPRINTF(f, "Usage: %s [OPTION]... PATH\n", name);
 	FPRINTF(f,
 		"\n"
+		"  -t, --tcp-ports SPEC	TCP inbound port forwarding\n"
+		"    can be specified multiple times\n"
+		"    SPEC can be:\n"
+		"      'none': don't forward any ports\n"
+		"      [ADDR[%%IFACE]/]PORTS: forward specific ports\n"
+		"        PORTS is either 'all' (forward all unbound, non-ephemeral\n"
+		"        ports), or a comma-separated list of ports, optionally\n"
+		"        ranged with '-' and optional target ports after ':'.\n"
+		"        Ranges can be reduced by excluding ports or ranges\n"
+		"        prefixed by '~'.\n"
+		"        The 'auto' keyword may be given to only forward\n"
+		"        ports which are bound in the target namespace\n"
+		"        Examples:\n"
+		"        -t all         Forward all ports\n"
+		"        -t 127.0.0.1/all Forward all ports from local address\n"
+		"                         127.0.0.1\n"
+		"        -t 22		Forward local port 22 to 22\n"
+		"        -t 22:23	Forward local port 22 to 23\n"
+		"        -t 22,25	Forward ports 22, 25 to ports 22, 25\n"
+		"        -t 22-80  	Forward ports 22 to 80\n"
+		"        -t 22-80:32-90	Forward ports 22 to 80 to\n"
+		"			corresponding port numbers plus 10\n"
+		"        -t 192.0.2.1/5	Bind port 5 of 192.0.2.1\n"
+		"        -t 5-25,~10-20	Forward ports 5 to 9, and 21 to 25\n"
+		"        -t ~25		Forward all ports except for 25\n"
+		"        -t auto	Forward all ports bound in namespace\n"
+		"        -t 192.0.2.2/auto Forward ports from 192.0.2.2 if\n"
+		"                          they are bound in the namespace\n"
+		"        -t 8000-8010,auto Forward ports 8000-8010 if they\n"
+		"                          are bound in the namespace\n"
+		"  -u, --udp-ports SPEC	UDP inbound port forwarding\n"
+		"    SPEC is as described for TCP above\n"
+		"  -T, --tcp-ns SPEC	TCP port forwarding to init namespace\n"
+		"    SPEC is as described above\n"
+		"  -U, --udp-ns SPEC	UDP port forwarding to init namespace\n"
+		"    SPEC is as described above\n"
+		"  -s, --show		Show configuration before and after\n"
 		"  -d, --debug		Print debugging messages\n"
 		"  -h, --help		Display this help message and exit\n"
 		"  --version		Show version and exit\n");
@@ -207,6 +244,8 @@ static void show_conf(const struct configuration *conf)
 		fwd_rules_dump(printf, pc->fwd.rules, pc->fwd.count,
 			       "    ", "\n");
 	}
+	/* Flush stdout, so this doesn't get misordered with later debug()s */
+	(void)fflush(stdout);
 }
 
 /**
@@ -218,7 +257,7 @@ static void show_conf(const struct configuration *conf)
  *
  * #syscalls:pesto socket s390x:socketcall i686:socketcall
  * #syscalls:pesto connect shutdown close
- * #syscalls:pesto exit_group fstat read write
+ * #syscalls:pesto exit_group fstat read write openat
  */
 int main(int argc, char **argv)
 {
@@ -226,11 +265,18 @@ int main(int argc, char **argv)
 		{"debug",	no_argument,		NULL,		'd' },
 		{"help",	no_argument,		NULL,		'h' },
 		{"version",	no_argument,		NULL,		1 },
+		{"tcp-ports",	required_argument,	NULL,		't' },
+		{"udp-ports",	required_argument,	NULL,		'u' },
+		{"tcp-ns",	required_argument,	NULL,		'T' },
+		{"udp-ns",	required_argument,	NULL,		'U' },
+		{"show",	no_argument,		NULL,		's' },
 		{ 0 },
 	};
+	struct pif_configuration *inbound, *outbound;
 	struct sockaddr_un a = { AF_UNIX, "" };
+	const char *optstring = "dht:u:T:U:s";
 	struct configuration conf = { 0 };
-	const char *optstring = "dh";
+	bool update = false, show = false;
 	struct pesto_hello hello;
 	struct sock_fprog prog;
 	int optname, ret, s;
@@ -251,6 +297,8 @@ int main(int argc, char **argv)
 	if (setvbuf(stdout, stdout_buf, _IOFBF, sizeof(stdout_buf)))
 		die_perror("Failed to set stdout buffer");
 
+	fwd_probe_ephemeral();
+
 	do {
 		optname = getopt_long(argc, argv, optstring, options, NULL);
 
@@ -258,6 +306,16 @@ int main(int argc, char **argv)
 		case -1:
 		case 0:
 			break;
+		case 't':
+		case 'u':
+		case 'T':
+		case 'U':
+			/* Parse these options after we've read state from passt/pasta */
+			update = true;
+			break;
+		case 's':
+			show = true;
+			break;
 		case 'h':
 			usage(argv[0], stdout, EXIT_SUCCESS);
 			break;
@@ -290,6 +348,8 @@ int main(int argc, char **argv)
 		die_perror("Failed to connect to %s", a.sun_path);
 	}
 
+	debug("Connected to passt/pasta control socket");
+
 	ret = read_all_buf(s, &hello, sizeof(hello));
 	if (ret < 0)
 		die_perror("Couldn't read server greeting");
@@ -327,9 +387,52 @@ int main(int argc, char **argv)
 	while (read_pif_conf(s, &conf))
 		;
 
-	printf("passt/pasta configuration (%s)\n", a.sun_path);
-	show_conf(&conf);
+	if (!update) {
+		printf("passt/pasta configuration (%s)\n", a.sun_path);
+		show_conf(&conf);
+		goto noupdate;
+	}
+
+	if (show) {
+		printf("Previous configuration (%s)\n", a.sun_path);
+		show_conf(&conf);
+	}
+
+	inbound = pif_conf_by_name(&conf, "HOST");
+	outbound = pif_conf_by_name(&conf, "SPLICE");
+
+	optind = 0;
+	do {
+		optname = getopt_long(argc, argv, optstring, options, NULL);
+
+		switch (optname) {
+		case 't':
+		case 'u':
+			if (!inbound) {
+				die("Can't use -%c, no inbound interface",
+				    optname);
+			}
+			fwd_rule_parse(optname, optarg, &inbound->fwd);
+			break;
+		case 'T':
+		case 'U':
+			if (!outbound) {
+				die("Can't use -%c, no outbound interface",
+				    optname);
+			}
+			fwd_rule_parse(optname, optarg, &outbound->fwd);
+			break;
+		default:
+			continue;
+		}
+	} while (optname != -1);
+
+	if (show) {
+		printf("Updated configuration (%s)\n", a.sun_path);
+		show_conf(&conf);
+	}
 
+noupdate:
 	if (shutdown(s, SHUT_RDWR) < 0 || close(s) < 0)
 		die_perror("Error shutting down control socket");
 
-- 
2.43.0