From 09be87bbee1e4338b488f22199d0f079ffec8d0e Mon Sep 17 00:00:00 2001 From: Kevin Krakauer Date: Mon, 29 Jul 2019 13:18:58 -0700 Subject: Add iptables types for syscalls tests. Unfortunately, Linux's ip_tables.h header doesn't compile in C++ because it implicitly converts from void* to struct xt_entry_target*. C allows this, but C++ does not. So we have to re-implement many types ourselves. Relevant code here: https://github.com/torvalds/linux/blob/master/include/uapi/linux/netfilter_ipv4/ip_tables.h#L222 PiperOrigin-RevId: 260565570 --- test/syscalls/linux/BUILD | 8 ++ test/syscalls/linux/iptables.h | 198 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 206 insertions(+) create mode 100644 test/syscalls/linux/iptables.h diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD index c5a368463..40fc73812 100644 --- a/test/syscalls/linux/BUILD +++ b/test/syscalls/linux/BUILD @@ -904,6 +904,14 @@ cc_binary( ], ) +cc_library( + name = "iptables_types", + testonly = 1, + hdrs = [ + "iptables.h", + ], +) + cc_binary( name = "itimer_test", testonly = 1, diff --git a/test/syscalls/linux/iptables.h b/test/syscalls/linux/iptables.h new file mode 100644 index 000000000..616bea550 --- /dev/null +++ b/test/syscalls/linux/iptables.h @@ -0,0 +1,198 @@ +// Copyright 2019 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// There are a number of structs and values that we can't #include because of a +// difference between C and C++ (C++ won't let you implicitly cast from void* to +// struct something*). We re-define them here. + +#ifndef GVISOR_TEST_SYSCALLS_IPTABLES_TYPES_H_ +#define GVISOR_TEST_SYSCALLS_IPTABLES_TYPES_H_ + +// Netfilter headers require some headers to preceed them. +// clang-format off +#include +#include +// clang-format on + +#include +#include +#include +#include +#include + +#define ipt_standard_target xt_standard_target +#define ipt_entry_target xt_entry_target +#define ipt_error_target xt_error_target + +enum SockOpts { + // For setsockopt. + BASE_CTL = 64, + SO_SET_REPLACE = BASE_CTL, + SO_SET_ADD_COUNTERS, + SO_SET_MAX = SO_SET_ADD_COUNTERS, + + // For getsockopt. + SO_GET_INFO = BASE_CTL, + SO_GET_ENTRIES, + SO_GET_REVISION_MATCH, + SO_GET_REVISION_TARGET, + SO_GET_MAX = SO_GET_REVISION_TARGET +}; + +// ipt_ip specifies basic matching criteria that can be applied by examining +// only the IP header of a packet. +struct ipt_ip { + // Source IP address. + struct in_addr src; + + // Destination IP address. + struct in_addr dst; + + // Source IP address mask. + struct in_addr smsk; + + // Destination IP address mask. + struct in_addr dmsk; + + // Input interface. + char iniface[IFNAMSIZ]; + + // Output interface. + char outiface[IFNAMSIZ]; + + // Input interface mask. + unsigned char iniface_mask[IFNAMSIZ]; + + // Output interface mask. + unsigned char outiface_mask[IFNAMSIZ]; + + // Transport protocol. + uint16_t proto; + + // Flags. + uint8_t flags; + + // Inverse flags. + uint8_t invflags; +}; + +// ipt_entry is an iptables rule. It contains information about what packets the +// rule matches and what action (target) to perform for matching packets. +struct ipt_entry { + // Basic matching information used to match a packet's IP header. + struct ipt_ip ip; + + // A caching field that isn't used by userspace. + unsigned int nfcache; + + // The number of bytes between the start of this ipt_entry struct and the + // rule's target. + uint16_t target_offset; + + // The total size of this rule, from the beginning of the entry to the end of + // the target. + uint16_t next_offset; + + // A return pointer not used by userspace. + unsigned int comefrom; + + // Counters for packets and bytes, which we don't yet implement. + struct xt_counters counters; + + // The data for all this rules matches followed by the target. This runs + // beyond the value of sizeof(struct ipt_entry). + unsigned char elems[0]; +}; + +// Passed to getsockopt(SO_GET_INFO). +struct ipt_getinfo { + // The name of the table. The user only fills this in, the rest is filled in + // when returning from getsockopt. Currently "nat" and "mangle" are supported. + char name[XT_TABLE_MAXNAMELEN]; + + // A bitmap of which hooks apply to the table. For example, a table with hooks + // PREROUTING and FORWARD has the value + // (1 << NF_IP_PRE_REOUTING) | (1 << NF_IP_FORWARD). + unsigned int valid_hooks; + + // The offset into the entry table for each valid hook. The entry table is + // returned by getsockopt(SO_GET_ENTRIES). + unsigned int hook_entry[NF_IP_NUMHOOKS]; + + // For each valid hook, the underflow is the offset into the entry table to + // jump to in case traversing the table yields no verdict (although I have no + // clue how that could happen - builtin chains always end with a policy, and + // user-defined chains always end with a RETURN. + // + // The entry referred to must be an "unconditional" entry, meaning it has no + // matches, specifies no IP criteria, and either DROPs or ACCEPTs packets. It + // basically has to be capable of making a definitive decision no matter what + // it's passed. + unsigned int underflow[NF_IP_NUMHOOKS]; + + // The number of entries in the entry table returned by + // getsockopt(SO_GET_ENTRIES). + unsigned int num_entries; + + // The size of the entry table returned by getsockopt(SO_GET_ENTRIES). + unsigned int size; +}; + +// Passed to getsockopt(SO_GET_ENTRIES). +struct ipt_get_entries { + // The name of the table. The user fills this in. Currently "nat" and "mangle" + // are supported. + char name[XT_TABLE_MAXNAMELEN]; + + // The size of the entry table in bytes. The user fills this in with the value + // from struct ipt_getinfo.size. + unsigned int size; + + // The entries for the given table. This will run past the size defined by + // sizeof(struct ipt_get_entries). + struct ipt_entry entrytable[0]; +}; + +// Passed to setsockopt(SO_SET_REPLACE). +struct ipt_replace { + // The name of the table. + char name[XT_TABLE_MAXNAMELEN]; + + // The same as struct ipt_getinfo.valid_hooks. Users don't change this. + unsigned int valid_hooks; + + // The same as struct ipt_getinfo.num_entries. + unsigned int num_entries; + + // The same as struct ipt_getinfo.size. + unsigned int size; + + // The same as struct ipt_getinfo.hook_entry. + unsigned int hook_entry[NF_IP_NUMHOOKS]; + + // The same as struct ipt_getinfo.underflow. + unsigned int underflow[NF_IP_NUMHOOKS]; + + // The number of counters, which should equal the number of entries. + unsigned int num_counters; + + // The unchanged values from each ipt_entry's counters. + struct xt_counters *counters; + + // The entries to write to the table. This will run past the size defined by + // sizeof(srtuct ipt_replace); + struct ipt_entry entries[0]; +}; + +#endif // GVISOR_TEST_SYSCALLS_IPTABLES_TYPES_H_ -- cgit v1.2.3