From bd940a4efd2b5897f8a8e58ec7733417b3710e1e Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Wed, 8 Dec 2021 13:28:49 +0100
Subject: [PATCH] mnl: do not build nftnl_set element list
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2047821
Upstream Status: nftables commit b4b234f5a29e8
Conflicts: Context change due to missing commit 66746e7dedeb0
("src: support for nat with interval concatenation").
commit b4b234f5a29e819045679acd95820a7457d4d7de
Author: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Thu Nov 4 12:53:11 2021 +0100
mnl: do not build nftnl_set element list
Do not call alloc_setelem_cache() to build the set element list in
nftnl_set. Instead, translate one single set element expression to
nftnl_set_elem object at a time and use this object to build the netlink
header.
Using a huge test set containing 1.1 million element blocklist, this
patch is reducing userspace memory consumption by 40%.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
include/netlink.h | 2 +
src/mnl.c | 112 ++++++++++++++++++++++++++++++++++++----------
src/netlink.c | 4 +-
3 files changed, 93 insertions(+), 25 deletions(-)
diff --git a/include/netlink.h b/include/netlink.h
index 059092e..3443582 100644
--- a/include/netlink.h
+++ b/include/netlink.h
@@ -56,6 +56,8 @@ struct netlink_ctx {
extern struct nftnl_expr *alloc_nft_expr(const char *name);
extern void alloc_setelem_cache(const struct expr *set, struct nftnl_set *nls);
+struct nftnl_set_elem *alloc_nftnl_setelem(const struct expr *set,
+ const struct expr *expr);
extern struct nftnl_table *netlink_table_alloc(const struct nlmsghdr *nlh);
extern struct nftnl_chain *netlink_chain_alloc(const struct nlmsghdr *nlh);
diff --git a/src/mnl.c b/src/mnl.c
index 23341e6..44cf1a4 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -1201,33 +1201,102 @@ static int set_elem_cb(const struct nlmsghdr *nlh, void *data)
return MNL_CB_OK;
}
-static int mnl_nft_setelem_batch(struct nftnl_set *nls,
+static bool mnl_nft_attr_nest_overflow(struct nlmsghdr *nlh,
+ const struct nlattr *from,
+ const struct nlattr *to)
+{
+ int len = (void *)to + to->nla_len - (void *)from;
+
+ /* The attribute length field is 16 bits long, thus the maximum payload
+ * that an attribute can convey is UINT16_MAX. In case of overflow,
+ * discard the last attribute that did not fit into the nest.
+ */
+ if (len > UINT16_MAX) {
+ nlh->nlmsg_len -= to->nla_len;
+ return true;
+ }
+ return false;
+}
+
+static void netlink_dump_setelem(const struct nftnl_set_elem *nlse,
+ struct netlink_ctx *ctx)
+{
+ FILE *fp = ctx->nft->output.output_fp;
+ char buf[4096];
+
+ if (!(ctx->nft->debug_mask & NFT_DEBUG_NETLINK) || !fp)
+ return;
+
+ nftnl_set_elem_snprintf(buf, sizeof(buf), nlse, NFTNL_OUTPUT_DEFAULT, 0);
+ fprintf(fp, "\t%s", buf);
+}
+
+static void netlink_dump_setelem_done(struct netlink_ctx *ctx)
+{
+ FILE *fp = ctx->nft->output.output_fp;
+
+ if (!(ctx->nft->debug_mask & NFT_DEBUG_NETLINK) || !fp)
+ return;
+
+ fprintf(fp, "\n");
+}
+
+static int mnl_nft_setelem_batch(const struct nftnl_set *nls,
struct nftnl_batch *batch,
enum nf_tables_msg_types cmd,
- unsigned int flags, uint32_t seqnum)
+ unsigned int flags, uint32_t seqnum,
+ const struct expr *set,
+ struct netlink_ctx *ctx)
{
+ struct nlattr *nest1, *nest2;
+ struct nftnl_set_elem *nlse;
struct nlmsghdr *nlh;
- struct nftnl_set_elems_iter *iter;
- int ret;
-
- iter = nftnl_set_elems_iter_create(nls);
- if (iter == NULL)
- memory_allocation_error();
+ struct expr *expr = NULL;
+ int i = 0;
if (cmd == NFT_MSG_NEWSETELEM)
flags |= NLM_F_CREATE;
- while (nftnl_set_elems_iter_cur(iter)) {
- nlh = nftnl_nlmsg_build_hdr(nftnl_batch_buffer(batch), cmd,
- nftnl_set_get_u32(nls, NFTNL_SET_FAMILY),
- flags, seqnum);
- ret = nftnl_set_elems_nlmsg_build_payload_iter(nlh, iter);
- mnl_nft_batch_continue(batch);
- if (ret <= 0)
- break;
+ if (set)
+ expr = list_first_entry(&set->expressions, struct expr, list);
+
+next:
+ nlh = nftnl_nlmsg_build_hdr(nftnl_batch_buffer(batch), cmd,
+ nftnl_set_get_u32(nls, NFTNL_SET_FAMILY),
+ flags, seqnum);
+
+ if (nftnl_set_is_set(nls, NFTNL_SET_TABLE)) {
+ mnl_attr_put_strz(nlh, NFTA_SET_ELEM_LIST_TABLE,
+ nftnl_set_get_str(nls, NFTNL_SET_TABLE));
+ }
+ if (nftnl_set_is_set(nls, NFTNL_SET_NAME)) {
+ mnl_attr_put_strz(nlh, NFTA_SET_ELEM_LIST_SET,
+ nftnl_set_get_str(nls, NFTNL_SET_NAME));
}
+ if (nftnl_set_is_set(nls, NFTNL_SET_ID)) {
+ mnl_attr_put_u32(nlh, NFTA_SET_ELEM_LIST_SET_ID,
+ htonl(nftnl_set_get_u32(nls, NFTNL_SET_ID)));
+ }
+
+ if (!set || list_empty(&set->expressions))
+ return 0;
- nftnl_set_elems_iter_destroy(iter);
+ assert(expr);
+ nest1 = mnl_attr_nest_start(nlh, NFTA_SET_ELEM_LIST_ELEMENTS);
+ list_for_each_entry_from(expr, &set->expressions, list) {
+ nlse = alloc_nftnl_setelem(set, expr);
+ nest2 = nftnl_set_elem_nlmsg_build(nlh, nlse, ++i);
+ netlink_dump_setelem(nlse, ctx);
+ nftnl_set_elem_free(nlse);
+ if (mnl_nft_attr_nest_overflow(nlh, nest1, nest2)) {
+ mnl_attr_nest_end(nlh, nest1);
+ mnl_nft_batch_continue(batch);
+ goto next;
+ }
+ }
+ mnl_attr_nest_end(nlh, nest1);
+ mnl_nft_batch_continue(batch);
+ netlink_dump_setelem_done(ctx);
return 0;
}
@@ -1249,11 +1318,10 @@ int mnl_nft_setelem_add(struct netlink_ctx *ctx, const struct set *set,
if (h->set_id)
nftnl_set_set_u32(nls, NFTNL_SET_ID, h->set_id);
- alloc_setelem_cache(expr, nls);
netlink_dump_set(nls, ctx);
- err = mnl_nft_setelem_batch(nls, ctx->batch, NFT_MSG_NEWSETELEM, flags,
- ctx->seqnum);
+ err = mnl_nft_setelem_batch(nls, ctx->batch, NFT_MSG_NEWSETELEM,
+ flags, ctx->seqnum, expr, ctx);
nftnl_set_free(nls);
return err;
@@ -1306,12 +1374,10 @@ int mnl_nft_setelem_del(struct netlink_ctx *ctx, const struct cmd *cmd)
else if (h->handle.id)
nftnl_set_set_u64(nls, NFTNL_SET_HANDLE, h->handle.id);
- if (cmd->expr)
- alloc_setelem_cache(cmd->expr, nls);
netlink_dump_set(nls, ctx);
err = mnl_nft_setelem_batch(nls, ctx->batch, NFT_MSG_DELSETELEM, 0,
- ctx->seqnum);
+ ctx->seqnum, cmd->expr, ctx);
nftnl_set_free(nls);
return err;
diff --git a/src/netlink.c b/src/netlink.c
index 825c2cc..f8c97d0 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -95,8 +95,8 @@ struct nftnl_expr *alloc_nft_expr(const char *name)
return nle;
}
-static struct nftnl_set_elem *alloc_nftnl_setelem(const struct expr *set,
- const struct expr *expr)
+struct nftnl_set_elem *alloc_nftnl_setelem(const struct expr *set,
+ const struct expr *expr)
{
const struct expr *elem, *data;
struct nftnl_set_elem *nlse;
--
2.31.1