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Kernel: More work on ICMP support.

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We can now kinda sorta respond to ICMP::EchoRequest although there's
still something not entirely right with the packets.
This commit is contained in:
Andreas Kling 2019-03-12 04:39:50 +01:00
parent 5bd9844dd6
commit 75e0ddd46a
3 changed files with 13 additions and 18 deletions
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17
Kernel/ICMP.h
View file

@ -25,27 +25,22 @@ public:
word checksum() const { return ntohs(m_checksum); } word checksum() const { return ntohs(m_checksum); }
void set_checksum(word w) { m_checksum = htons(w); } void set_checksum(word w) { m_checksum = htons(w); }
const void* payload() const { return &m_payload[0]; } const void* payload() const { return this + 1; }
void* payload() { return &m_payload[0]; } void* payload() { return this + 1; }
private: private:
byte m_type { 0 }; byte m_type { 0 };
byte m_code { 0 }; byte m_code { 0 };
word m_checksum { 0 }; word m_checksum { 0 };
dword m_rest_of_header { 0 }; // NOTE: The rest of the header is 4 bytes
byte m_payload[0];
}; };
static_assert(sizeof(ICMPHeader) == 8); static_assert(sizeof(ICMPHeader) == 4);
struct [[gnu::packed]] IPv4ICMPPacket {
IPv4Packet ipv4_packet;
ICMPHeader icmp_header;
};
struct [[gnu::packed]] ICMPEchoPacket { struct [[gnu::packed]] ICMPEchoPacket {
ICMPHeader header; ICMPHeader header;
NetworkOrdered<word> identifier; NetworkOrdered<word> identifier;
NetworkOrdered<word> sequence_number; NetworkOrdered<word> sequence_number;
byte payload[]; void* payload() { return this + 1; }
const void* payload() const { return this + 1; }
}; };

5
Kernel/IPv4Packet.h
View file

@ -38,8 +38,8 @@ public:
const IPv4Address& destination() const { return m_destination; } const IPv4Address& destination() const { return m_destination; }
void set_destination(const IPv4Address& address) { m_destination = address; } void set_destination(const IPv4Address& address) { m_destination = address; }
void* payload() { return m_payload; } void* payload() { return this + 1; }
const void* payload() const { return m_payload; } const void* payload() const { return this + 1; }
private: private:
byte m_version_and_ihl; byte m_version_and_ihl;
@ -52,7 +52,6 @@ private:
word m_checksum; word m_checksum;
IPv4Address m_source; IPv4Address m_source;
IPv4Address m_destination; IPv4Address m_destination;
byte m_payload[0];
}; };
static_assert(sizeof(IPv4Packet) == 20); static_assert(sizeof(IPv4Packet) == 20);

9
Kernel/NetworkTask.cpp
View file

@ -156,6 +156,7 @@ void handle_ipv4(const EthernetFrameHeader& eth, int frame_size)
void handle_icmp(const EthernetFrameHeader& eth, int frame_size) void handle_icmp(const EthernetFrameHeader& eth, int frame_size)
{ {
(void)frame_size;
auto& ipv4_packet = *static_cast<const IPv4Packet*>(eth.payload()); auto& ipv4_packet = *static_cast<const IPv4Packet*>(eth.payload());
auto& icmp_header = *static_cast<const ICMPHeader*>(ipv4_packet.payload()); auto& icmp_header = *static_cast<const ICMPHeader*>(ipv4_packet.payload());
kprintf("handle_icmp: type=%b, code=%b\n", icmp_header.type(), icmp_header.code()); kprintf("handle_icmp: type=%b, code=%b\n", icmp_header.type(), icmp_header.code());
@ -165,7 +166,7 @@ void handle_icmp(const EthernetFrameHeader& eth, int frame_size)
// It's for me! // It's for me!
if (icmp_header.type() == ICMPType::EchoRequest) { if (icmp_header.type() == ICMPType::EchoRequest) {
auto& request = reinterpret_cast<const ICMPEchoPacket&>(icmp_header); auto& request = reinterpret_cast<const ICMPEchoPacket&>(icmp_header);
kprintf("ICMP echo request: id=%u, seq=%u\n", (int)request.identifier, (int)request.sequence_number); kprintf("ICMP echo request: id=%u, seq=%u, len=%u\n", (int)request.identifier, (int)request.sequence_number, ipv4_packet.length() - sizeof(ICMPEchoPacket));
byte* response_buffer = (byte*)kmalloc(ipv4_packet.length()); byte* response_buffer = (byte*)kmalloc(ipv4_packet.length());
memset(response_buffer, 0, ipv4_packet.length()); memset(response_buffer, 0, ipv4_packet.length());
struct [[gnu::packed]] EchoResponse { struct [[gnu::packed]] EchoResponse {
@ -178,13 +179,13 @@ void handle_icmp(const EthernetFrameHeader& eth, int frame_size)
response.ipv4.set_source(e1000.ipv4_address()); response.ipv4.set_source(e1000.ipv4_address());
response.ipv4.set_destination(ipv4_packet.source()); response.ipv4.set_destination(ipv4_packet.source());
response.ipv4.set_protocol(IPv4Protocol::ICMP); response.ipv4.set_protocol(IPv4Protocol::ICMP);
response.ipv4.set_length(sizeof(IPv4ICMPPacket)); response.ipv4.set_length(ipv4_packet.length());
response.icmp_echo.header.set_type(ICMPType::EchoReply); response.icmp_echo.header.set_type(ICMPType::EchoReply);
response.icmp_echo.header.set_code(0); response.icmp_echo.header.set_code(0);
response.icmp_echo.identifier = request.identifier; response.icmp_echo.identifier = request.identifier;
response.icmp_echo.sequence_number = request.sequence_number; response.icmp_echo.sequence_number = request.sequence_number;
memcpy(response.icmp_echo.payload, request.payload, ipv4_packet.length() - sizeof(ICMPEchoPacket)); memcpy(response.icmp_echo.payload(), request.payload(), ipv4_packet.length() - sizeof(EchoResponse));
e1000.send_ipv4(eth.source(), &response, ipv4_packet.length()); e1000.send_ipv4(eth.source(), response_buffer, ipv4_packet.length());
kfree(response_buffer); kfree(response_buffer);
} }
} }