Sockets services

bsd:u / bsd:s

This is "nn::socket::sf::IClient".

Cmd	Name
0	RegisterClient (Initialize)
1	StartMonitoring
2	#Socket
3	#SocketExempt
4	#Open
5	Select
6	Poll
7	#Sysctl
8	Recv
9	RecvFrom
10	Send
11	SendTo
12	Accept
13	Bind
14	Connect
15	GetPeerName
16	GetSockName
17	GetSockOpt
18	Listen
19	#Ioctl
20	#Fcntl
21	SetSockOpt
22	Shutdown
23	ShutdownAllSockets
24	Write
25	Read
26	Close
27	#DuplicateSocket
28	GetResourceStatistics
29	[3.0.0+] RecvMMsg
30	[3.0.0+] SendMMsg

Initalize

Takes a #BsdBufferConfig (made-up name), the PID, the size of the transfer memory and a copy-handle of the latter.

BsdBufferConfig

/// Configuration structure for bsdInitalize
typedef struct  {
    u32 version;                ///< Observed 1 on 2.0 LibAppletWeb, 2 on 3.0.

    u32 tcp_tx_buf_size;        ///< Size of the TCP transfer (send) buffer (initial or fixed).
    u32 tcp_rx_buf_size;        ///< Size of the TCP recieve buffer (initial or fixed).
    u32 tcp_tx_buf_max_size;    ///< Maximum size of the TCP transfer (send) buffer. If it is 0, the size of the buffer is fixed to its initial value.
    u32 tcp_rx_buf_max_size;    ///< Maximum size of the TCP receive buffer. If it is 0, the size of the buffer is fixed to its initial value.

    u32 udp_tx_buf_size;        ///< Size of the UDP transfer (send) buffer (typically 0x2400 bytes).
    u32 udp_rx_buf_size;        ///< Size of the UDP receive buffer (typically 0xA500 bytes).

    u32 sb_efficiency;          ///< Number of buffers for each socket (standard values range from 1 to 8).
} BsdBufferConfig;

The transfer memory must be larger than a the computed size below. Should the transfer memory be smaller than that, the BSD sockets service would only send ZeroWindow packets (for TCP), resulting in a transfer rate not exceeding 1 byte/s.

static size_t _bsdGetTransferMemSizeForBufferConfig(const BsdBufferConfig *config)
{
    u32 tcp_tx_buf_max_size = config->tcp_tx_buf_max_size != 0 ? config->tcp_tx_buf_max_size : config->tcp_tx_buf_size;
    u32 tcp_rx_buf_max_size = config->tcp_rx_buf_max_size != 0 ? config->tcp_rx_buf_max_size : config->tcp_rx_buf_size;
    u32 sum = tcp_tx_buf_max_size + tcp_rx_buf_max_size + config->udp_tx_buf_size + config->udp_rx_buf_size;

    sum = ((sum + 0xFFF) >> 12) << 12; // page round-up
    return (size_t)(config->sb_efficiency * sum);
}

Socket

FreeBSD's socket command. bsd:u disallows the usage of the SOCK_SEQPACKET and SOCK_RAW types, with the exception of (AF_INET, SOCK_RAW, IPPROTO_ICMP) (IPv4 ping), bsd:s needs to be used for those.

The only registered domains are AF_INET and AF_ROUTE.

SocketExempt: same as socket but the socket is immediately shutdown (disconnected) on creation.

Open

FreeBSD's open command, limited to opening /dev/bpf. This can be used, for example, to enable promiscuous mode, see FreeBSD's /dev/bpf for more details.

Sysctl

FreeBSD's sysctl command, restricted to CTL_NET (?). Privileged operations are reserved for bsd:s.

Ioctl

FreeBSD's ioctl function. The following ioctls are whitelisted, refer to FreeBSD's headers for more details: SIOCATMARK, BIOCGBLEN, BIOCSETF BIOCIMMEDIATE, BIOCSETIF, BIOCVERSION, FIONSPACE, FIONWRITE, FIONREAD, SIOCGETSGCNT, SIOCGIFMETRIC, SIOCSIFMETRIC, SIOCDIFADDR, SIOCGIFINDEX, SIOCGIFADDR, SIOCGIFCONF, SIOCGIFNETMASK, SIOCAIFADDR, SIOCGIFMTU, SIOCSIFMTU, SIOCGIFMEDIA, SIOCSIFLLADDR and SIOCGIFXMEDIA.

Nintendo use the following definition (hence changing all ioctls using this structure):

struct bpf_program {
	u_int bf_len;
	struct bpf_insn bf_insns[BPF_MAXINSNS]; // [512]. This is a pointer in the official structure
};

Fcntl

FreeBSD's fcntl, limited to F_GETFL and F_SETFL with O_NONBLOCK.

DuplicateSocket

Takes a socket file descriptor and an unused u64. Duplicates the socket (FreeBSD's dup). Reserved to bsd:s.

sfdnsres

This is "nn::socket::resolver::IResolver".

Cmd	Name
0	SetDnsAddressesPrivate (stubbed, returns 0x7FE03)
1	GetDnsAddressPrivate (stubbed, returns 0x7FE03)
2	GetHostByName
3	GetHostByAddr
4	GetHostStringError
5	GetGaiStringError
6	#GetAddrInfo
7	GetNameInfo
8	RequestCancelHandle
9	CancelSocketCall
10	?
11	#ClearDnsIpServerAddressArray (made-up name)

GetAddrInfo

Takes three type 5 buffers (host, port, and hints), and a type 6 buffer (the output addrinfos). Also takes a u8 (padded to 4 bytes so the next raw parameter can align), a u32, and a u64. The u8 is a boolean for whether to enable "nsd resolve" (1) or not (0). Not sure what the u32 is. It seems to either come from a parameter to GetAddrInfo or be zero. The u64 is most likely a placeholder for the server to copy the PID into and should be zero. Both hints and the output buffer contain serialized addrinfo chains. The hints buffer is sized 0x400 bytes long by default, and the output buffer 0x1000 bytes.

Addrinfo Serialization Format

Each struct addrinfo in the linked list is serialized according to this format and then written to the buffer. All numbers are in network byte order.

Size (bytes)	Name	Notes
4	Magic	Needs to be 0xBEEFCAFE. Seriously.
4	ai_flags
4	ai_family
4	ai_socktype
4	ai_protocol
4	ai_addrlen
ai_addrlen ? ai_addrlen : 4	ai_addr
null-terminated string	ai_canonname

If ai_addrlen is zero, ai_addr will occupy 4 bytes.

Size (bytes)	Name	Notes
4	ai_addr

If ai_family is recognized as AF_INET6 (28) or AF_INET (2), ai_addr is read as struct sockaddr_in or struct sockaddr_in6. Otherwise, it's just read as u8[ai_addrlen].

The list should be terminated with a sentinel four-byte zero value.

ClearDnsIpServerAddressArray

This function clears nn::socket::resolver::g_DnsIpServerAddressArray, setting its length to 0 as well. The array initially contains IPs filled by bsdconfig, a privileged service handling DHCP and such.

Takes no arguments, doesn't return anything, never fails.

nsd:u / nsd:a

This is "nn::nsd::detail::IManager".

Cmd	Name
10	GetSettingName
11	GetEnvironmentIdentifier
12	GetDeviceId
13	DeleteSettings
14	ImportSettings
20	Resolve
21	ResolveEx
30	GetNasServiceSetting
31	GetNasServiceSettingEx
40	GetNasRequestFqdn
41	GetNasRequestFqdnEx
42	GetNasApiFqdn
43	GetNasApiFqdnEx
50	GetCurrentSetting
60	#ReadSaveDataFromFsForTest
61	#WriteSaveDataToFsForTest
62	#DeleteSaveDataOfFsForTest

ReadSaveDataFromFsForTest

Requires the nsd!test_mode setting to be equal to 1.

Mounts the system save data for bsdsockets as nsdsave and reads from nsd:/file to the specified buffer, at the specified size and offset with no checks whatsoever. nsdsave is then unmounted.

WriteSaveDataToFsForTest

Requires the nsd!test_mode setting to be equal to 1.

Mounts the system save data for bsdsockets as nsdsave and writes to nsd:/file (appending is allowed) using the specified buffer, at the specified size and offset, with no checks whatsoever. nsdsave is then commited and unmounted.

DeleteSaveDataOfFsForTest

Requires the nsd!test_mode setting to be equal to 1.

Deletes the system save data for bsdsockets.