In order to support the same ruleset sizes as legacy iptables, the
kernel's limit of 1024 iovecs has to be overcome. Therefore increase
each iovec's size from 128KB to 2MB.
While being at it, add a log message for failing sendmsg() call. This is
not supposed to happen, even if the transaction fails. Yet if it does,
users are left with only a "line XXX failed" message (with line number
being the COMMIT line).
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
Changes since v1:
- Drop getpagesize() call, no real use for that.
- Adjust comment and description to account for the actual page size.
---
iptables/nft.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/iptables/nft.c b/iptables/nft.c
index bd840e75f83f4..4e80e5b7e7972 100644
--- a/iptables/nft.c
+++ b/iptables/nft.c
@@ -88,11 +88,11 @@ int mnl_talk(struct nft_handle *h, struct nlmsghdr *nlh,
#define NFT_NLMSG_MAXSIZE (UINT16_MAX + getpagesize())
-/* selected batch page is 256 Kbytes long to load ruleset of
- * half a million rules without hitting -EMSGSIZE due to large
- * iovec.
+/* Selected batch page is 2 Mbytes long to support loading a ruleset of 3.5M
+ * rules matching on source and destination address as well as input and output
+ * interfaces. This is what legacy iptables supports.
*/
-#define BATCH_PAGE_SIZE getpagesize() * 32
+#define BATCH_PAGE_SIZE 2 * 1024 * 1024
static struct nftnl_batch *mnl_batch_init(void)
{
@@ -220,8 +220,10 @@ static int mnl_batch_talk(struct nft_handle *h, int numcmds)
int err = 0;
ret = mnl_nft_socket_sendmsg(h, numcmds);
- if (ret == -1)
+ if (ret == -1) {
+ fprintf(stderr, "sendmsg() failed: %s\n", strerror(errno));
return -1;
+ }
FD_ZERO(&readfds);
FD_SET(fd, &readfds);
--
2.31.0
