diff options
| author | Beniamino Galvani <bgalvani@redhat.com> | 2022-03-14 11:05:28 +0100 |
|---|---|---|
| committer | Thomas Haller <thaller@redhat.com> | 2022-04-13 11:05:12 +0200 |
| commit | 74382182100d686cc6b09641c4d434030e7de861 (patch) | |
| tree | 6277544669b150aa8086dbfbb4fdcf9f468a2ea2 | |
| parent | 0c6d242dc0b67b6269657acf33bf9d1f0830f0b4 (diff) | |
n-dhcp4/connection: dynamically allocate the receive buffer
Each connection object includes a 64KiB scratch buffer used for
receiving packets. When many instances of the client are created,
those buffers use a significant amount of memory. For example, 500
clients take ~30MiB of memory constantly reserved only for those
buffers.
Since the buffer is used only in the function and is never passed
outside, a stack allocation would suffice; however, it's not wise to
do such large allocations on the stack; dynamically allocate it.
https://github.com/nettools/n-dhcp4/issues/26
https://github.com/nettools/n-dhcp4/pull/27
https://github.com/nettools/n-dhcp4/commit/64513e31c01a88db54c89321f89bcc85da27ffc5
(cherry picked from commit a5a5654f187535d0d60f508bd44fff16f036d536)
| -rw-r--r-- | src/n-dhcp4/src/n-dhcp4-c-connection.c | 17 | ||||
| -rw-r--r-- | src/n-dhcp4/src/n-dhcp4-private.h | 9 |
2 files changed, 11 insertions, 15 deletions
diff --git a/src/n-dhcp4/src/n-dhcp4-c-connection.c b/src/n-dhcp4/src/n-dhcp4-c-connection.c index 2f660e3b30..65328286e8 100644 --- a/src/n-dhcp4/src/n-dhcp4-c-connection.c +++ b/src/n-dhcp4/src/n-dhcp4-c-connection.c @@ -1147,16 +1147,21 @@ int n_dhcp4_c_connection_dispatch_timer(NDhcp4CConnection *connection, int n_dhcp4_c_connection_dispatch_io(NDhcp4CConnection *connection, NDhcp4Incoming **messagep) { _c_cleanup_(n_dhcp4_incoming_freep) NDhcp4Incoming *message = NULL; + _c_cleanup_(c_freep) uint8_t *buffer = NULL; char serv_addr[INET_ADDRSTRLEN]; char client_addr[INET_ADDRSTRLEN]; uint8_t type = 0; int r; + buffer = malloc(UINT16_MAX); + if (!buffer) + return -ENOMEM; + switch (connection->state) { case N_DHCP4_C_CONNECTION_STATE_PACKET: r = n_dhcp4_c_socket_packet_recv(connection->fd_packet, - connection->scratch_buffer, - sizeof(connection->scratch_buffer), + buffer, + UINT16_MAX, &message); if (!r) break; @@ -1165,8 +1170,8 @@ int n_dhcp4_c_connection_dispatch_io(NDhcp4CConnection *connection, return N_DHCP4_E_AGAIN; case N_DHCP4_C_CONNECTION_STATE_DRAINING: r = n_dhcp4_c_socket_packet_recv(connection->fd_packet, - connection->scratch_buffer, - sizeof(connection->scratch_buffer), + buffer, + UINT16_MAX, &message); if (!r) break; @@ -1188,8 +1193,8 @@ int n_dhcp4_c_connection_dispatch_io(NDhcp4CConnection *connection, /* fall-through */ case N_DHCP4_C_CONNECTION_STATE_UDP: r = n_dhcp4_c_socket_udp_recv(connection->fd_udp, - connection->scratch_buffer, - sizeof(connection->scratch_buffer), + buffer, + UINT16_MAX, &message); if (!r) break; diff --git a/src/n-dhcp4/src/n-dhcp4-private.h b/src/n-dhcp4/src/n-dhcp4-private.h index 191e946e70..858c3d3ab0 100644 --- a/src/n-dhcp4/src/n-dhcp4-private.h +++ b/src/n-dhcp4/src/n-dhcp4-private.h @@ -334,15 +334,6 @@ struct NDhcp4CConnection { uint32_t client_ip; /* client IP address, or 0 */ uint32_t server_ip; /* server IP address, or 0 */ uint16_t mtu; /* client mtu, or 0 */ - - /* - * When we get DHCP packets from the kernel, we need a buffer to read - * the data into. Since UDP packets can be up to 2^16 bytes in size, we - * avoid placing it on the stack and instead read into this scratch - * buffer. It is purely meant as stack replacement, no data is returned - * through this buffer. - */ - uint8_t scratch_buffer[UINT16_MAX]; }; #define N_DHCP4_C_CONNECTION_NULL(_x) { \ |