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use crate::block::*; use byteorder::{BigEndian, ByteOrder, LittleEndian}; use failure::Fail; use std::io; use std::result; use std::time::SystemTime; pub type Result<T> = result::Result<T, Error>; #[derive(Debug, Fail)] pub enum Error { #[fail(display = "Didn't understand magic number {:?}", _0)] DidntUnderstandMagicNumber([u8; 4]), #[fail(display = "Not enough bytes (expected {}, saw {})", _0, _1)] NotEnoughBytes { expected: usize, actual: usize }, #[fail(display = "Section didn't start with an SHB")] DidntStartWithSHB, #[fail(display = "Block's start and end lengths don't match")] BlockLengthMismatch, #[fail(display = "Block length must be at least 12 bytes")] BlockLengthTooShort, #[fail(display = "option_len for if_tsresol should be 1 but got {}", _0)] WrongOptionLen(usize), #[fail(display = "There were more options after an option with type 0")] OptionsAfterEnd, #[fail(display = "This timestamp resolution won't fit into a u32")] ResolutionTooHigh, #[fail(display = "IO error: {}", _0)] IO(#[cause] io::Error), } impl From<io::Error> for Error { fn from(x: io::Error) -> Error { Error::IO(x) } } /// A single captured packet. #[derive(Debug, Clone, PartialEq)] pub struct Packet<'a> { /// The time at which the packet was captured. The resolution depends on the interface. pub timestamp: Option<SystemTime>, /// The interface used to capture this packet. pub interface: Option<&'a Interface>, /// The raw packet data. pub data: &'a [u8], } /// The type of physical link backing a network interface. #[allow(non_camel_case_types)] #[derive(Debug, Clone, PartialEq, Copy)] pub enum LinkType { /// No link layer information. A packet saved with this link layer contains a raw L3 packet /// preceded by a 32-bit host-byte-order AF_ value indicating the specific L3 type. NULL, /// D/I/X and 802.3 Ethernet ETHERNET, /// Experimental Ethernet (3Mb) EXP_ETHERNET, /// Amateur Radio AX.25 AX24, /// Proteon ProNET Token Ring PRONET, /// Chaos CHAOS, /// IEEE 802 Networks TOKEN_RING, /// ARCNET, with BSD-style header ARCNET, /// Serial Line IP SLIP, /// Point-to-point Protocol PPP, /// FDDI FDDI, /// PPP in HDLC-like framing PPP_HDLC, /// NetBSD PPP-over-Ethernet PPP_ETHER, /// Symantec Enterprise Firewall SYMANTEC_FIREWALL, /// LLC/SNAP-encapsulated ATM ATM_RFC1483, /// Raw IP RAW, /// BSD/OS SLIP BPF header SLIP_BSDOS, /// BSD/OS PPP BPF header PPP_BSDOS, /// Cisco HDLC C_HDLC, /// IEEE 802.11 (wireless) IEEE802_11, /// Linux Classical IP over ATM ATM_CLIP, /// Frame Relay FRELAY, /// OpenBSD loopback LOOP, /// OpenBSD IPSEC enc ENC, /// ATM LANE + 802.3 (Reserved for future use) LANE8023, /// NetBSD HIPPI (Reserved for future use) HIPPI, /// NetBSD HDLC framing (Reserved for future use) HDLC, /// Linux cooked socket capture LINUX_SLL, /// Apple LocalTalk hardware LTALK, /// Acorn Econet ECONET, /// Reserved for use with OpenBSD ipfilter IPFILTER, /// OpenBSD DLT_PFLOG PFLOG, /// For Cisco-internal use CISCO_IOS, /// 802.11+Prism II monitor mode PRISM_HEADER, /// FreeBSD Aironet driver stuff AIRONET_HEADER, /// Reserved for Siemens HiPath HDLC HHDLC, /// RFC 2625 IP-over-Fibre Channel IP_OVER_FC, /// Solaris+SunATM SUNATM, /// RapidIO - Reserved as per request from Kent Dahlgren <kent@praesum.com> for private use. RIO, /// PCI Express - Reserved as per request from Kent Dahlgren <kent@praesum.com> for private /// use. PCI_EXP, /// Xilinx Aurora link layer - Reserved as per request from Kent Dahlgren <kent@praesum.com> /// for private use. AURORA, /// 802.11 plus BSD radio header IEEE802_11_RADIO, /// Tazmen Sniffer Protocol - Reserved for the TZSP encapsulation, as per request from Chris /// Waters <chris.waters@networkchemistry.com> TZSP is a generic encapsulation for any other /// link type, which includes a means to include meta-information with the packet, e.g. signal /// strength and channel for 802.11 packets. TZSP, /// Linux-style headers ARCNET_LINUX, /// Juniper-private data link type, as per request from Hannes Gredler <hannes@juniper.net>. /// The corresponding DLT_s are used for passing on chassis-internal metainformation such as /// QOS profiles, etc.. JUNIPER_MLPPP, /// Juniper-private data link type, as per request from Hannes Gredler <hannes@juniper.net>. /// The corresponding DLT_s are used for passing on chassis-internal metainformation such as /// QOS profiles, etc.. JUNIPER_MLFR, /// Juniper-private data link type, as per request from Hannes Gredler <hannes@juniper.net>. /// The corresponding DLT_s are used for passing on chassis-internal metainformation such as /// QOS profiles, etc.. JUNIPER_ES, /// Juniper-private data link type, as per request from Hannes Gredler <hannes@juniper.net>. /// The corresponding DLT_s are used for passing on chassis-internal metainformation such as /// QOS profiles, etc.. JUNIPER_GGSN, /// Juniper-private data link type, as per request from Hannes Gredler <hannes@juniper.net>. /// The corresponding DLT_s are used for passing on chassis-internal metainformation such as /// QOS profiles, etc.. JUNIPER_MFR, /// Juniper-private data link type, as per request from Hannes Gredler <hannes@juniper.net>. /// The corresponding DLT_s are used for passing on chassis-internal metainformation such as /// QOS profiles, etc.. JUNIPER_ATM2, /// Juniper-private data link type, as per request from Hannes Gredler <hannes@juniper.net>. /// The corresponding DLT_s are used for passing on chassis-internal metainformation such as /// QOS profiles, etc.. JUNIPER_SERVICES, /// Juniper-private data link type, as per request from Hannes Gredler <hannes@juniper.net>. /// The corresponding DLT_s are used for passing on chassis-internal metainformation such as /// QOS profiles, etc.. JUNIPER_ATM1, /// Apple IP-over-IEEE 1394 cooked header APPLE_IP_OVER_IEEE1394, /// ??? MTP2_WITH_PHDR, /// ??? MTP2, /// ??? MTP3, /// ??? SCCP, /// DOCSIS MAC frames DOCSIS, /// Linux-IrDA LINUX_IRDA, /// Reserved for IBM SP switch and IBM Next Federation switch. IBM_SP, /// Reserved for IBM SP switch and IBM Next Federation switch. IBM_SN, /// A link type we didn't recognise. Unknown(u16), } impl LinkType { /// Decode LinkType from u16 pub fn from_u16(i: u16) -> LinkType { match i { 0 => LinkType::NULL, 1 => LinkType::ETHERNET, 2 => LinkType::EXP_ETHERNET, 3 => LinkType::AX24, 4 => LinkType::PRONET, 5 => LinkType::CHAOS, 6 => LinkType::TOKEN_RING, 7 => LinkType::ARCNET, 8 => LinkType::SLIP, 9 => LinkType::PPP, 10 => LinkType::FDDI, 50 => LinkType::PPP_HDLC, 51 => LinkType::PPP_ETHER, 99 => LinkType::SYMANTEC_FIREWALL, 100 => LinkType::ATM_RFC1483, 101 => LinkType::RAW, 102 => LinkType::SLIP_BSDOS, 103 => LinkType::PPP_BSDOS, 104 => LinkType::C_HDLC, 105 => LinkType::IEEE802_11, 106 => LinkType::ATM_CLIP, 107 => LinkType::FRELAY, 108 => LinkType::LOOP, 109 => LinkType::ENC, 110 => LinkType::LANE8023, 111 => LinkType::HIPPI, 112 => LinkType::HDLC, 113 => LinkType::LINUX_SLL, 114 => LinkType::LTALK, 115 => LinkType::ECONET, 116 => LinkType::IPFILTER, 117 => LinkType::PFLOG, 118 => LinkType::CISCO_IOS, 119 => LinkType::PRISM_HEADER, 120 => LinkType::AIRONET_HEADER, 121 => LinkType::HHDLC, 122 => LinkType::IP_OVER_FC, 123 => LinkType::SUNATM, 124 => LinkType::RIO, 125 => LinkType::PCI_EXP, 126 => LinkType::AURORA, 127 => LinkType::IEEE802_11_RADIO, 128 => LinkType::TZSP, 129 => LinkType::ARCNET_LINUX, 130 => LinkType::JUNIPER_MLPPP, 131 => LinkType::JUNIPER_MLFR, 132 => LinkType::JUNIPER_ES, 133 => LinkType::JUNIPER_GGSN, 134 => LinkType::JUNIPER_MFR, 135 => LinkType::JUNIPER_ATM2, 136 => LinkType::JUNIPER_SERVICES, 137 => LinkType::JUNIPER_ATM1, 138 => LinkType::APPLE_IP_OVER_IEEE1394, 139 => LinkType::MTP2_WITH_PHDR, 140 => LinkType::MTP2, 141 => LinkType::MTP3, 142 => LinkType::SCCP, 143 => LinkType::DOCSIS, 144 => LinkType::LINUX_IRDA, 145 => LinkType::IBM_SP, 146 => LinkType::IBM_SN, // LINKTYPE_RAW is defined as 101 in the registry but for some reason libpcap uses DLT_RAW // defined as 14 on OpenBSD and as 12 for other platforms for the link type. So in order to // reliably decode link types we need to remap those numbers as LinkType::RAW here. 12 => LinkType::RAW, 14 => LinkType::RAW, x => LinkType::Unknown(x), } } } #[derive(Clone, PartialEq, Debug, Copy)] pub enum Endianness { Big, Little, } impl Endianness { pub fn parse_from_magic(buf: &[u8]) -> Result<Self> { let magic = &buf[0..4]; match magic { [0x1A, 0x2B, 0x3C, 0x4D] => Ok(Endianness::Big), [0x4D, 0x3C, 0x2B, 0x1A] => Ok(Endianness::Little), _ => { let mut unknown_magic = [0; 4]; unknown_magic.copy_from_slice(magic); Err(Error::DidntUnderstandMagicNumber(unknown_magic)) } } } } pub trait KnownByteOrder { fn endianness() -> Endianness; } impl KnownByteOrder for BigEndian { fn endianness() -> Endianness { Endianness::Big } } impl KnownByteOrder for LittleEndian { fn endianness() -> Endianness { Endianness::Little } } #[derive(Clone, PartialEq, Debug, Copy)] pub struct InterfaceId(pub u32); pub trait FromBytes<'a>: Sized { fn parse<B: ByteOrder + KnownByteOrder>(buf: &'a [u8]) -> Result<Self>; } pub fn require_bytes(buf: &[u8], len: usize) -> Result<()> { if buf.len() < len { Err(Error::NotEnoughBytes { expected: len, actual: buf.len(), }) } else { Ok(()) } } /// A network interface. #[derive(Debug, Clone, Copy, PartialEq)] pub struct Interface { pub link_type: LinkType, /// The if_tsresol option identifies the resolution of timestamps. If the Most Significant Bit /// is equal to zero, the remaining bits indicates the resolution of the timestamp as a negative /// power of 10 (e.g. 6 means microsecond resolution, timestamps are the number of microseconds /// since 1/1/1970). If the Most Significant Bit is equal to one, the remaining bits indicates /// the resolution as as negative power of 2 (e.g. 10 means 1/1024 of second). If this option is /// not present, a resolution of 10^-6 is assumed (i.e. timestamps have the same resolution of /// the standard 'libpcap' timestamps). pub(crate) units_per_sec: u32, } impl Interface { pub(crate) fn from_desc<B: ByteOrder>(desc: &InterfaceDescription) -> Result<Interface> { let mut units_per_sec = 1_000_000; let mut i = 0; loop { if desc.options.len() < i + 4 { // no further options break; } let option_type = B::read_u16(&desc.options[i..i + 2]); i += 2; let option_len = B::read_u16(&desc.options[i..i + 2]) as usize; i += 2; match option_type { 0 => { // end of options if i != desc.options.len() { return Err(Error::OptionsAfterEnd); } break; } 9 => { // if_tsresol if option_len != 1 { return Err(Error::WrongOptionLen(option_len)); } let v = desc.options[i]; let exp = u32::from(v & 0b0111_1111); match v >> 7 { 0 => { units_per_sec = checked_pow(10_u32, exp).ok_or(Error::ResolutionTooHigh)? } 1 => { units_per_sec = checked_pow(2_u32, exp).ok_or(Error::ResolutionTooHigh)? } _ => { /* impossible */ } } } _ => { /* skip other option types */ } } let padding_len = (4 - option_len % 4) % 4; i += option_len + padding_len; } Ok(Interface { link_type: desc.link_type, units_per_sec, }) } } // TODO: Remove this when `checked_pow` lands in stable #[inline] pub fn checked_pow(mut base: u32, mut exp: u32) -> Option<u32> { let mut acc: u32 = 1; while exp > 1 { if (exp & 1) == 1 { acc = acc.checked_mul(base)?; } exp /= 2; base = base.checked_mul(base)?; } // Deal with the final bit of the exponent separately, since // squaring the base afterwards is not necessary and may cause a // needless overflow. if exp == 1 { acc = acc.checked_mul(base)?; } Some(acc) }