Repository : ssh://git@diktynna/alfred
On branch : master
commit 5935c1e910927cf446a251c232fc75af558aff8d Author: Sven Eckelmann sven@narfation.org Date: Tue Jan 4 10:11:02 2022 +0100
alfred: Avoid large send buffer for fixed size IPC commands
For data related IPC commands, a buffer of 65527 bytes is necessary to send or receive a complete command. But for non-data related IPC commands usually have a fixed size. It is therefore enough to allocate exactly the minimum required amount of bytes on the stack for non-data related IPC commands.
Signed-off-by: Sven Eckelmann sven@narfation.org Acked-by: Marek Lindner mareklindner@neomailbox.ch
5935c1e910927cf446a251c232fc75af558aff8d client.c | 83 +++++++++++++++++++++++++++++----------------------------------- 1 file changed, 38 insertions(+), 45 deletions(-)
diff --git a/client.c b/client.c index e1107bf..b5faf3b 100644 --- a/client.c +++ b/client.c @@ -23,7 +23,7 @@ int alfred_client_request_data(struct globals *globals) { unsigned char buf[MAX_PAYLOAD], *pos; - struct alfred_request_v0 *request; + struct alfred_request_v0 request; struct alfred_push_data_v0 *push; struct alfred_status_v0 *status; struct alfred_tlv *tlv; @@ -34,17 +34,16 @@ int alfred_client_request_data(struct globals *globals) if (unix_sock_open_client(globals)) return -1;
- request = (struct alfred_request_v0 *)buf; - len = sizeof(*request); + len = sizeof(request);
- request->header.type = ALFRED_REQUEST; - request->header.version = ALFRED_VERSION; - request->header.length = sizeof(*request) - sizeof(request->header); - request->header.length = htons(request->header.length); - request->requested_type = globals->clientmode_arg; - request->tx_id = get_random_id(); + request.header.type = ALFRED_REQUEST; + request.header.version = ALFRED_VERSION; + request.header.length = sizeof(request) - sizeof(request.header); + request.header.length = htons(request.header.length); + request.requested_type = globals->clientmode_arg; + request.tx_id = get_random_id();
- ret = write(globals->unix_sock, buf, len); + ret = write(globals->unix_sock, &request, len); if (ret != len) fprintf(stderr, "%s: only wrote %d of %d bytes: %s\n", __func__, ret, len, strerror(errno)); @@ -179,26 +178,24 @@ int alfred_client_set_data(struct globals *globals)
int alfred_client_modeswitch(struct globals *globals) { - unsigned char buf[MAX_PAYLOAD]; - struct alfred_modeswitch_v0 *modeswitch; + struct alfred_modeswitch_v0 modeswitch; int ret, len;
if (unix_sock_open_client(globals)) return -1;
- modeswitch = (struct alfred_modeswitch_v0 *)buf; - len = sizeof(*modeswitch); + len = sizeof(modeswitch);
- modeswitch->header.type = ALFRED_MODESWITCH; - modeswitch->header.version = ALFRED_VERSION; - modeswitch->header.length = htons(len - sizeof(modeswitch->header)); + modeswitch.header.type = ALFRED_MODESWITCH; + modeswitch.header.version = ALFRED_VERSION; + modeswitch.header.length = htons(len - sizeof(modeswitch.header));
switch (globals->opmode) { case OPMODE_SECONDARY: - modeswitch->mode = ALFRED_MODESWITCH_SECONDARY; + modeswitch.mode = ALFRED_MODESWITCH_SECONDARY; break; case OPMODE_PRIMARY: - modeswitch->mode = ALFRED_MODESWITCH_PRIMARY; + modeswitch.mode = ALFRED_MODESWITCH_PRIMARY; break; default: fprintf(stderr, "%s: unknown opmode %u in modeswitch\n", @@ -206,7 +203,7 @@ int alfred_client_modeswitch(struct globals *globals) return -1; }
- ret = write(globals->unix_sock, buf, len); + ret = write(globals->unix_sock, &modeswitch, len); if (ret != len) fprintf(stderr, "%s: only wrote %d of %d bytes: %s\n", __func__, ret, len, strerror(errno)); @@ -248,8 +245,7 @@ static int check_interface(const char *iface)
int alfred_client_change_interface(struct globals *globals) { - unsigned char buf[MAX_PAYLOAD]; - struct alfred_change_interface_v0 *change_interface; + struct alfred_change_interface_v0 change_interface; int ret, len; char *input, *token, *saveptr; size_t interface_len; @@ -258,24 +254,23 @@ int alfred_client_change_interface(struct globals *globals) return -1;
interface_len = strlen(globals->change_interface); - if (interface_len > sizeof(change_interface->ifaces)) { + if (interface_len > sizeof(change_interface.ifaces)) { fprintf(stderr, "%s: interface name list too long, not changing\n", __func__); return 0; }
- change_interface = (struct alfred_change_interface_v0 *)buf; - len = sizeof(*change_interface); + len = sizeof(change_interface);
- change_interface->header.type = ALFRED_CHANGE_INTERFACE; - change_interface->header.version = ALFRED_VERSION; - change_interface->header.length = htons(len - sizeof(change_interface->header)); - strncpy(change_interface->ifaces, globals->change_interface, - sizeof(change_interface->ifaces)); - change_interface->ifaces[sizeof(change_interface->ifaces) - 1] = '\0'; + change_interface.header.type = ALFRED_CHANGE_INTERFACE; + change_interface.header.version = ALFRED_VERSION; + change_interface.header.length = htons(len - sizeof(change_interface.header)); + strncpy(change_interface.ifaces, globals->change_interface, + sizeof(change_interface.ifaces)); + change_interface.ifaces[sizeof(change_interface.ifaces) - 1] = '\0';
/* test it before sending - * globals->change_interface is now saved in change_interface->ifaces + * globals->change_interface is now saved in change_interface.ifaces * and can be modified by strtok_r */ input = globals->change_interface; @@ -287,7 +282,7 @@ int alfred_client_change_interface(struct globals *globals) return 0; }
- ret = write(globals->unix_sock, buf, len); + ret = write(globals->unix_sock, &change_interface, len); if (ret != len) fprintf(stderr, "%s: only wrote %d of %d bytes: %s\n", __func__, ret, len, strerror(errno)); @@ -299,8 +294,7 @@ int alfred_client_change_interface(struct globals *globals)
int alfred_client_change_bat_iface(struct globals *globals) { - unsigned char buf[MAX_PAYLOAD]; - struct alfred_change_bat_iface_v0 *change_bat_iface; + struct alfred_change_bat_iface_v0 change_bat_iface; int ret, len; size_t interface_len;
@@ -308,23 +302,22 @@ int alfred_client_change_bat_iface(struct globals *globals) return -1;
interface_len = strlen(globals->mesh_iface); - if (interface_len > sizeof(change_bat_iface->bat_iface)) { + if (interface_len > sizeof(change_bat_iface.bat_iface)) { fprintf(stderr, "%s: batman-adv interface name list too long, not changing\n", __func__); return 0; }
- change_bat_iface = (struct alfred_change_bat_iface_v0 *)buf; - len = sizeof(*change_bat_iface); + len = sizeof(change_bat_iface);
- change_bat_iface->header.type = ALFRED_CHANGE_BAT_IFACE; - change_bat_iface->header.version = ALFRED_VERSION; - change_bat_iface->header.length = htons(len - sizeof(change_bat_iface->header)); - strncpy(change_bat_iface->bat_iface, globals->mesh_iface, - sizeof(change_bat_iface->bat_iface)); - change_bat_iface->bat_iface[sizeof(change_bat_iface->bat_iface) - 1] = '\0'; + change_bat_iface.header.type = ALFRED_CHANGE_BAT_IFACE; + change_bat_iface.header.version = ALFRED_VERSION; + change_bat_iface.header.length = htons(len - sizeof(change_bat_iface.header)); + strncpy(change_bat_iface.bat_iface, globals->mesh_iface, + sizeof(change_bat_iface.bat_iface)); + change_bat_iface.bat_iface[sizeof(change_bat_iface.bat_iface) - 1] = '\0';
- ret = write(globals->unix_sock, buf, len); + ret = write(globals->unix_sock, &change_bat_iface, len); if (ret != len) fprintf(stderr, "%s: only wrote %d of %d bytes: %s\n", __func__, ret, len, strerror(errno));