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passt/passt.h
David Gibson 7c7b68dbe0 Use typing to reduce chances of IPv4 endianness errors 
We recently corrected some errors handling the endianness of IPv4
addresses.  These are very easy errors to make since although we mostly
store them in network endianness, we sometimes need to manipulate them in
host endianness.

To reduce the chances of making such mistakes again, change to always using
a (struct in_addr) instead of a bare in_addr_t or uint32_t to store network
endian addresses.  This makes it harder to accidentally do arithmetic or
comparisons on such addresses as if they were host endian.

We introduce a number of IN4_IS_ADDR_*() helpers to make it easier to
directly work with struct in_addr values.  This has the additional benefit
of making the IPv4 and IPv6 paths more visually similar.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-11-04 12:04:24 +01:00

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/* SPDX-License-Identifier: AGPL-3.0-or-later
* Copyright (c) 2021 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#ifndef PASST_H
#define PASST_H
#define UNIX_SOCK_MAX 100
#define UNIX_SOCK_PATH "/tmp/passt_%i.socket"
/**
* struct tap_msg - Generic message descriptor for arrays of messages
* @pkt_buf_offset: Offset from @pkt_buf
* @len: Message length, with L2 headers
*/
struct tap_msg {
uint32_t pkt_buf_offset;
uint16_t len;
};
/**
* struct tap_l4_msg - Layer-4 message descriptor for protocol handlers
* @pkt_buf_offset: Offset of message from @pkt_buf
* @l4_len: Length of Layer-4 payload, host order
*/
struct tap_l4_msg {
uint32_t pkt_buf_offset;
uint16_t l4_len;
};
union epoll_ref;
#include "packet.h"
#include "icmp.h"
#include "port_fwd.h"
#include "tcp.h"
#include "udp.h"
/**
* union epoll_ref - Breakdown of reference for epoll socket bookkeeping
* @proto: IP protocol number
* @s: Socket number (implies 2^24 limit on number of descriptors)
* @tcp: TCP-specific reference part
* @udp: UDP-specific reference part
* @icmp: ICMP-specific reference part
* @data: Data handled by protocol handlers
* @u64: Opaque reference for epoll_ctl() and epoll_wait()
*/
union epoll_ref {
struct {
int32_t proto:8,
#define SOCKET_REF_BITS 24
#define SOCKET_MAX (1 << SOCKET_REF_BITS)
s:SOCKET_REF_BITS;
union {
union tcp_epoll_ref tcp;
union udp_epoll_ref udp;
union icmp_epoll_ref icmp;
uint32_t data;
} p;
} r;
uint64_t u64;
};
#define TAP_BUF_BYTES \
ROUND_DOWN(((ETH_MAX_MTU + sizeof(uint32_t)) * 128), PAGE_SIZE)
#define TAP_BUF_FILL (TAP_BUF_BYTES - ETH_MAX_MTU - sizeof(uint32_t))
#define TAP_MSGS \
DIV_ROUND_UP(TAP_BUF_BYTES, ETH_ZLEN - 2 * ETH_ALEN + sizeof(uint32_t))
#define PKT_BUF_BYTES MAX(TAP_BUF_BYTES, 0)
extern char pkt_buf [PKT_BUF_BYTES];
extern char *ip_proto_str[];
#define IP_PROTO_STR(n) \
(((uint8_t)(n) <= IPPROTO_SCTP && ip_proto_str[(n)]) ? \
ip_proto_str[(n)] : "?")
#include <resolv.h> /* For MAXNS below */
/**
* struct fqdn - Representation of fully-qualified domain name
* @n: Domain name string
*/
struct fqdn {
char n[NS_MAXDNAME];
};
#include <net/if.h>
#include <linux/un.h>
enum passt_modes {
MODE_PASST,
MODE_PASTA,
};
/**
* struct ip4_ctx - IPv4 execution context
* @addr: IPv4 address for external, routable interface
* @addr_seen: Latest IPv4 address seen as source from tap
* @prefixlen: IPv4 prefix length (netmask)
* @gw: Default IPv4 gateway, network order
* @dns: IPv4 DNS addresses, zero-terminated, network order
* @dns_fwd: Address forwarded (UDP) to first IPv4 DNS, network order
*/
struct ip4_ctx {
struct in_addr addr;
struct in_addr addr_seen;
int prefix_len;
struct in_addr gw;
struct in_addr dns[MAXNS + 1];
struct in_addr dns_fwd;
};
/**
* struct ip6_ctx - IPv6 execution context
* @addr: IPv6 address for external, routable interface
* @addr_ll: Link-local IPv6 address on external, routable interface
* @addr_seen: Latest IPv6 global/site address seen as source from tap
* @addr_ll_seen: Latest IPv6 link-local address seen as source from tap
* @gw: Default IPv6 gateway
* @dns: IPv6 DNS addresses, zero-terminated
* @dns_fwd: Address forwarded (UDP) to first IPv6 DNS, network order
*/
struct ip6_ctx {
struct in6_addr addr;
struct in6_addr addr_ll;
struct in6_addr addr_seen;
struct in6_addr addr_ll_seen;
struct in6_addr gw;
struct in6_addr dns[MAXNS + 1];
struct in6_addr dns_fwd;
};
#include <netinet/if_ether.h>
/**
* struct ctx - Execution context
* @mode: Operation mode, qemu/UNIX domain socket or namespace/tap
* @debug: Enable debug mode
* @trace: Enable tracing (extra debug) mode
* @quiet: Don't print informational messages
* @foreground: Run in foreground, don't log to stderr by default
* @stderr: Force logging to stderr
* @nofile: Maximum number of open files (ulimit -n)
* @sock_path: Path for UNIX domain socket
* @pcap: Path for packet capture file
* @pid_file: Path to PID file, empty string if not configured
* @pasta_netns_fd: File descriptor for network namespace in pasta mode
* @no_netns_quit: In pasta mode, don't exit if fs-bound namespace is gone
* @netns_base: Base name for fs-bound namespace, if any, in pasta mode
* @netns_dir: Directory of fs-bound namespace, if any, in pasta mode
* @proc_net_tcp: Stored handles for /proc/net/tcp{,6} in init and ns
* @proc_net_udp: Stored handles for /proc/net/udp{,6} in init and ns
* @epollfd: File descriptor for epoll instance
* @fd_tap_listen: File descriptor for listening AF_UNIX socket, if any
* @fd_tap: File descriptor for AF_UNIX socket or tuntap device
* @mac: Host MAC address
* @mac_guest: MAC address of guest or namespace, seen or configured
* @ifi4: Index of routable interface for IPv4, 0 if IPv4 disabled
* @ip: IPv4 configuration
* @dns_search: DNS search list
* @ifi6: Index of routable interface for IPv6, 0 if IPv6 disabled
* @ip6: IPv6 configuration
* @pasta_ifn: Name of namespace interface for pasta
* @pasta_ifn: Index of namespace interface for pasta
* @pasta_conf_ns: Configure namespace interface after creating it
* @no_tcp: Disable TCP operation
* @tcp: Context for TCP protocol handler
* @no_tcp: Disable UDP operation
* @udp: Context for UDP protocol handler
* @no_icmp: Disable ICMP operation
* @icmp: Context for ICMP protocol handler
* @mtu: MTU passed via DHCP/NDP
* @no_dns: Do not source/use DNS servers for any purpose
* @no_dns_search: Do not source/use domain search lists for any purpose
* @no_dhcp_dns: Do not assign any DNS server via DHCP/DHCPv6/NDP
* @no_dhcp_dns_search: Do not assign any DNS domain search via DHCP/DHCPv6/NDP
* @no_dhcp: Disable DHCP server
* @no_dhcpv6: Disable DHCPv6 server
* @no_ndp: Disable NDP handler altogether
* @no_ra: Disable router advertisements
* @no_map_gw: Don't map connections, untracked UDP to gateway to host
* @low_wmem: Low probed net.core.wmem_max
* @low_rmem: Low probed net.core.rmem_max
*/
struct ctx {
enum passt_modes mode;
int debug;
int trace;
int quiet;
int foreground;
int stderr;
int nofile;
char sock_path[UNIX_PATH_MAX];
char pcap[PATH_MAX];
char pid_file[PATH_MAX];
int one_off;
int pasta_netns_fd;
int no_netns_quit;
char netns_base[PATH_MAX];
char netns_dir[PATH_MAX];
int proc_net_tcp[IP_VERSIONS][2];
int proc_net_udp[IP_VERSIONS][2];
int epollfd;
int fd_tap_listen;
int fd_tap;
unsigned char mac[ETH_ALEN];
unsigned char mac_guest[ETH_ALEN];
unsigned int ifi4;
struct ip4_ctx ip4;
struct fqdn dns_search[MAXDNSRCH];
unsigned int ifi6;
struct ip6_ctx ip6;
char pasta_ifn[IF_NAMESIZE];
unsigned int pasta_ifi;
int pasta_conf_ns;
int no_tcp;
struct tcp_ctx tcp;
int no_udp;
struct udp_ctx udp;
int no_icmp;
struct icmp_ctx icmp;
int mtu;
int no_dns;
int no_dns_search;
int no_dhcp_dns;
int no_dhcp_dns_search;
int no_dhcp;
int no_dhcpv6;
int no_ndp;
int no_ra;
int no_map_gw;
int low_wmem;
int low_rmem;
};
void proto_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
const struct in_addr *ip_da);
#endif /* PASST_H */
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