[PATCH v2 iproute2] utils: bump max args number to 512 for batch files

Large tc filters can have many arguments. For example the following
filter matches the first 7 MPLS LSEs, pops all of them, then updates
the Ethernet header and redirects the resulting packet to eth1.

filter add dev eth0 ingress handle 44 priority 100 \
  protocol mpls_uc flower mpls                     \
    lse depth 1 label 1040076 tc 4 bos 0 ttl 175   \
    lse depth 2 label 89648 tc 2 bos 0 ttl 9       \
    lse depth 3 label 63417 tc 5 bos 0 ttl 185     \
    lse depth 4 label 593135 tc 5 bos 0 ttl 67     \
    lse depth 5 label 857021 tc 0 bos 0 ttl 181    \
    lse depth 6 label 239239 tc 1 bos 0 ttl 254    \
    lse depth 7 label 30 tc 7 bos 1 ttl 237        \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol ipv6 pipe               \
  action vlan pop_eth pipe                         \
  action vlan push_eth                             \
    dst_mac 00:00:5e:00:53:7e                      \
    src_mac 00:00:5e:00:53:03 pipe                 \
  action mirred egress redirect dev eth1

This filter has 149 arguments, so it can't be used with tc -batch
which is limited to a 100.

Let's bump the limit to 512. That should leave a lot of room for big
batch commands.

v2:
   -Define the limit in utils.h (Stephen Hemminger)
   -Bump the limit even higher (256 -> 512) (Stephen Hemminger)

Signed-off-by: Guillaume Nault <redacted>
---
 include/utils.h | 3 +++
 lib/utils.c     | 4 ++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/utils.h b/include/utils.h
index 187444d5..5f5d8fa0 100644
--- a/include/utils.h
+++ b/include/utils.h

@@ -50,6 +50,9 @@ void incomplete_command(void) __attribute__((noreturn));
 #define NEXT_ARG_FWD() do { argv++; argc--; } while(0)
 #define PREV_ARG() do { argv--; argc++; } while(0)
 
+/* Upper limit for batch mode */
+#define MAX_ARGS 512
+
 #define TIME_UNITS_PER_SEC	1000000
 #define NSEC_PER_USEC 1000
 #define NSEC_PER_MSEC 1000000

diff --git a/lib/utils.c b/lib/utils.c
index 93ae0c55..0559923b 100644
--- a/lib/utils.c
+++ b/lib/utils.c

@@ -1714,10 +1714,10 @@ int do_batch(const char *name, bool force,
 
 	cmdlineno = 0;
 	while (getcmdline(&line, &len, stdin) != -1) {
-		char *largv[100];
+		char *largv[MAX_ARGS];
 		int largc;
 
-		largc = makeargs(line, largv, 100);
+		largc = makeargs(line, largv, MAX_ARGS);
 		if (!largc)
 			continue;	/* blank line */
 

-- 
2.21.3

On 6/11/21 3:46 AM, Guillaume Nault wrote:

Large tc filters can have many arguments. For example the following
filter matches the first 7 MPLS LSEs, pops all of them, then updates
the Ethernet header and redirects the resulting packet to eth1.

filter add dev eth0 ingress handle 44 priority 100 \
  protocol mpls_uc flower mpls                     \
    lse depth 1 label 1040076 tc 4 bos 0 ttl 175   \
    lse depth 2 label 89648 tc 2 bos 0 ttl 9       \
    lse depth 3 label 63417 tc 5 bos 0 ttl 185     \
    lse depth 4 label 593135 tc 5 bos 0 ttl 67     \
    lse depth 5 label 857021 tc 0 bos 0 ttl 181    \
    lse depth 6 label 239239 tc 1 bos 0 ttl 254    \
    lse depth 7 label 30 tc 7 bos 1 ttl 237        \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol mpls_uc pipe            \
  action mpls pop protocol ipv6 pipe               \
  action vlan pop_eth pipe                         \
  action vlan push_eth                             \
    dst_mac 00:00:5e:00:53:7e                      \
    src_mac 00:00:5e:00:53:03 pipe                 \
  action mirred egress redirect dev eth1

This filter has 149 arguments, so it can't be used with tc -batch
which is limited to a 100.

Let's bump the limit to 512. That should leave a lot of room for big
batch commands.

v2:
   -Define the limit in utils.h (Stephen Hemminger)
   -Bump the limit even higher (256 -> 512) (Stephen Hemminger)

Signed-off-by: Guillaume Nault <redacted>
---
 include/utils.h | 3 +++
 lib/utils.c     | 4 ++--
 2 files changed, 5 insertions(+), 2 deletions(-)

applied to iproute2-next. Thanks,