On Sat, Apr 03, 2021 at 10:49:40AM +0200, Phil Sutter wrote: > Hi, > > On Fri, Apr 02, 2021 at 07:38:10AM +0200, Florian Westphal wrote: > > Phil Sutter <phil@xxxxxx> wrote: > > > 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 256KB to 4MB. > > > > > > 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> > > > --- > > > iptables/nft.c | 12 +++++++----- > > > 1 file changed, 7 insertions(+), 5 deletions(-) > > > > > > diff --git a/iptables/nft.c b/iptables/nft.c > > > index bd840e75f83f4..e19c88ece6c2a 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 4 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 getpagesize() * 512 > > > > Why not remove getpagesize() altogether? > > Yes, why not. At least I couldn't find a reason in git log why it's > there in the first place. > > > The comment assumes getpagesize returns 4096 so might as well just use > > "#define BATCH_PAGE_SIZE (4 * 1024 * 1024)" or similar? > > > > On my system getpagesize() * 512 yields 2097152 ... > > Thanks for digging deeper, my comment was wrong. I believed the old > comment and assumed getpagesize() would return 256k / 32 = 8k but indeed > it returns 4k. NLMSG_GOODSIZE is not exposed to userspace, I was using it as reference. NLMSG_GOODSIZE is PAGE_SIZE.
