From a66b5ad9540dd64c7c67006201b8b3ccf8e4316b Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 19 Apr 2023 11:50:01 +0200 Subject: src: allow for updating devices on existing netdev chain This patch allows you to add/remove devices to an existing chain: # cat ruleset.nft table netdev x { chain y { type filter hook ingress devices = { eth0 } priority 0; policy accept; } } # nft -f ruleset.nft # nft add chain netdev x y '{ devices = { eth1 }; }' # nft list ruleset table netdev x { chain y { type filter hook ingress devices = { eth0, eth1 } priority 0; policy accept; } } # nft delete chain netdev x y '{ devices = { eth0 }; }' # nft list ruleset table netdev x { chain y { type filter hook ingress devices = { eth1 } priority 0; policy accept; } } This feature allows for creating an empty netdev chain, with no devices. In such case, no packets are seen until a device is registered. This patch includes extended netlink error reporting: # nft add chain netdev x y '{ devices = { x } ; }' Error: Could not process rule: No such file or directory add chain netdev x y { devices = { x } ; } ^ Signed-off-by: Pablo Neira Ayuso --- src/mnl.c | 109 ++++++++++++++++++++++++++++++++------------------------------ 1 file changed, 57 insertions(+), 52 deletions(-) (limited to 'src/mnl.c') diff --git a/src/mnl.c b/src/mnl.c index 4c16faca..c590c955 100644 --- a/src/mnl.c +++ b/src/mnl.c @@ -763,18 +763,34 @@ static void nft_dev_array_free(const struct nft_dev *dev_array) xfree(dev_array); } +static void mnl_nft_chain_devs_build(struct nlmsghdr *nlh, struct cmd *cmd) +{ + const struct expr *dev_expr = cmd->chain->dev_expr; + const struct nft_dev *dev_array; + struct nlattr *nest_dev; + int i, num_devs = 0; + + dev_array = nft_dev_array(dev_expr, &num_devs); + if (num_devs == 1) { + mnl_attr_put_strz(nlh, NFTA_HOOK_DEV, dev_array[0].ifname); + } else { + nest_dev = mnl_attr_nest_start(nlh, NFTA_HOOK_DEVS); + for (i = 0; i < num_devs; i++) { + cmd_add_loc(cmd, nlh->nlmsg_len, dev_array[i].location); + mnl_attr_put_strz(nlh, NFTA_DEVICE_NAME, dev_array[i].ifname); + mnl_attr_nest_end(nlh, nest_dev); + } + } + nft_dev_array_free(dev_array); +} + int mnl_nft_chain_add(struct netlink_ctx *ctx, struct cmd *cmd, unsigned int flags) { struct nftnl_udata_buf *udbuf; - int priority, policy, i = 0; struct nftnl_chain *nlc; - unsigned int ifname_len; - const char **dev_array; - char ifname[IFNAMSIZ]; struct nlmsghdr *nlh; - struct expr *expr; - int dev_array_len; + int priority, policy; nlc = nftnl_chain_alloc(); if (nlc == NULL) @@ -787,46 +803,6 @@ int mnl_nft_chain_add(struct netlink_ctx *ctx, struct cmd *cmd, nftnl_chain_set_u32(nlc, NFTNL_CHAIN_FLAGS, CHAIN_F_HW_OFFLOAD); } - if (cmd->chain->flags & CHAIN_F_BASECHAIN) { - nftnl_chain_set_u32(nlc, NFTNL_CHAIN_HOOKNUM, - cmd->chain->hook.num); - mpz_export_data(&priority, - cmd->chain->priority.expr->value, - BYTEORDER_HOST_ENDIAN, sizeof(int)); - nftnl_chain_set_s32(nlc, NFTNL_CHAIN_PRIO, priority); - nftnl_chain_set_str(nlc, NFTNL_CHAIN_TYPE, - cmd->chain->type.str); - } - if (cmd->chain->dev_expr) { - dev_array = xmalloc(sizeof(char *) * 8); - dev_array_len = 8; - list_for_each_entry(expr, &cmd->chain->dev_expr->expressions, list) { - ifname_len = div_round_up(expr->len, BITS_PER_BYTE); - memset(ifname, 0, sizeof(ifname)); - mpz_export_data(ifname, expr->value, - BYTEORDER_HOST_ENDIAN, - ifname_len); - dev_array[i++] = xstrdup(ifname); - if (i == dev_array_len) { - dev_array_len *= 2; - dev_array = xrealloc(dev_array, - dev_array_len * sizeof(char *)); - } - } - - dev_array[i] = NULL; - if (i == 1) - nftnl_chain_set_str(nlc, NFTNL_CHAIN_DEV, dev_array[0]); - else if (i > 1) - nftnl_chain_set_data(nlc, NFTNL_CHAIN_DEVICES, dev_array, - sizeof(char *) * dev_array_len); - - i = 0; - while (dev_array[i] != NULL) - xfree(dev_array[i++]); - - xfree(dev_array); - } if (cmd->chain->comment) { udbuf = nftnl_udata_buf_alloc(NFT_USERDATA_MAXLEN); if (!udbuf) @@ -861,12 +837,6 @@ int mnl_nft_chain_add(struct netlink_ctx *ctx, struct cmd *cmd, nftnl_chain_set_u32(nlc, NFTNL_CHAIN_FLAGS, cmd->chain->flags); } - if (cmd->chain && cmd->chain->flags & CHAIN_F_BASECHAIN) { - nftnl_chain_unset(nlc, NFTNL_CHAIN_TYPE); - cmd_add_loc(cmd, nlh->nlmsg_len, &cmd->chain->type.loc); - mnl_attr_put_strz(nlh, NFTA_CHAIN_TYPE, cmd->chain->type.str); - } - if (cmd->chain && cmd->chain->policy) { mpz_export_data(&policy, cmd->chain->policy->value, BYTEORDER_HOST_ENDIAN, sizeof(int)); @@ -874,7 +844,33 @@ int mnl_nft_chain_add(struct netlink_ctx *ctx, struct cmd *cmd, mnl_attr_put_u32(nlh, NFTA_CHAIN_POLICY, htonl(policy)); } + nftnl_chain_unset(nlc, NFTNL_CHAIN_TYPE); + nftnl_chain_nlmsg_build_payload(nlh, nlc); + + if (cmd->chain && cmd->chain->flags & CHAIN_F_BASECHAIN) { + struct nlattr *nest; + + if (cmd->chain->type.str) { + cmd_add_loc(cmd, nlh->nlmsg_len, &cmd->chain->type.loc); + mnl_attr_put_strz(nlh, NFTA_CHAIN_TYPE, cmd->chain->type.str); + } + + nest = mnl_attr_nest_start(nlh, NFTA_CHAIN_HOOK); + + if (cmd->chain->type.str) { + mnl_attr_put_u32(nlh, NFTA_HOOK_HOOKNUM, htonl(cmd->chain->hook.num)); + mpz_export_data(&priority, cmd->chain->priority.expr->value, + BYTEORDER_HOST_ENDIAN, sizeof(int)); + mnl_attr_put_u32(nlh, NFTA_HOOK_PRIORITY, htonl(priority)); + } + + if (cmd->chain && cmd->chain->dev_expr) + mnl_nft_chain_devs_build(nlh, cmd); + + mnl_attr_nest_end(nlh, nest); + } + nftnl_chain_free(nlc); mnl_nft_batch_continue(ctx->batch); @@ -943,6 +939,15 @@ int mnl_nft_chain_del(struct netlink_ctx *ctx, struct cmd *cmd) htobe64(cmd->handle.handle.id)); } + if (cmd->op == CMD_DELETE && + cmd->chain && cmd->chain->dev_expr) { + struct nlattr *nest; + + nest = mnl_attr_nest_start(nlh, NFTA_CHAIN_HOOK); + mnl_nft_chain_devs_build(nlh, cmd); + mnl_attr_nest_end(nlh, nest); + } + nftnl_chain_nlmsg_build_payload(nlh, nlc); nftnl_chain_free(nlc); -- cgit v1.2.3