Messages in this thread | | | From | Marc-André Lureau <> | Date | Wed, 8 Apr 2020 19:07:42 +0200 | Subject | Re: [PATCH] um: add a generic "fd" vector transport |
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Hi
On Tue, Apr 7, 2020 at 11:02 PM Anton Ivanov <anton.ivanov@cambridgegreys.com> wrote: > > On 07/04/2020 21:28, Marc-André Lureau wrote: > > Learn to take a pre-opened file-descriptor for vector IO. > > > > Instead of teaching the driver to open a FD in multiple ways, it can > > rely on management layer to do it on its behalf. For example, this > > allows inheriting a preconfigured device fd or a simple socketpair() > > setup, without further arguments, privileges or system access by UML. > > > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> > > --- > > arch/um/drivers/vector_user.c | 59 +++++++++++++++++++++++++++++++++++ > > 1 file changed, 59 insertions(+) > > > > diff --git a/arch/um/drivers/vector_user.c b/arch/um/drivers/vector_user.c > > index 29fae0456ade..45c1550dbb37 100644 > > --- a/arch/um/drivers/vector_user.c > > +++ b/arch/um/drivers/vector_user.c > > @@ -29,6 +29,7 @@ > > #include <netdb.h> > > #include <stdlib.h> > > #include <os.h> > > +#include <limits.h> > > #include <um_malloc.h> > > #include "vector_user.h" > > > > @@ -42,6 +43,9 @@ > > #define TRANS_RAW "raw" > > #define TRANS_RAW_LEN strlen(TRANS_RAW) > > > > +#define TRANS_FD "fd" > > +#define TRANS_FD_LEN strlen(TRANS_FD) > > + > > #define VNET_HDR_FAIL "could not enable vnet headers on fd %d" > > #define TUN_GET_F_FAIL "tapraw: TUNGETFEATURES failed: %s" > > #define L2TPV3_BIND_FAIL "l2tpv3_open : could not bind socket err=%i" > > @@ -347,6 +351,59 @@ static struct vector_fds *user_init_unix_fds(struct arglist *ifspec, int id) > > return NULL; > > } > > > > +static int strtofd(const char *nptr) > > +{ > > + long fd; > > + char *endptr; > > + > > + if (nptr == NULL) > > + return -1; > > + > > + errno = 0; > > + fd = strtol(nptr, &endptr, 10); > > + if (nptr == endptr || > > + errno != 0 || > > + *endptr != '\0' || > > + fd < 0 || > > + fd > INT_MAX) { > > + return -1; > > + } > > + return fd; > > +} > > + > > +static struct vector_fds *user_init_fd_fds(struct arglist *ifspec) > > +{ > > + int fd = -1; > > + char *fdarg = NULL; > > + struct vector_fds *result = NULL; > > + > > + fdarg = uml_vector_fetch_arg(ifspec, "fd"); > > + fd = strtofd(fdarg); > > + if (fd == -1) { > > + printk(UM_KERN_ERR "fd open: bad or missing fd argument"); > > + goto fd_cleanup; > > + } > > + > > + result = uml_kmalloc(sizeof(struct vector_fds), UM_GFP_KERNEL); > > + if (result == NULL) { > > + printk(UM_KERN_ERR "fd open: allocation failed"); > > + goto fd_cleanup; > > + } > > + > > + result->rx_fd = fd; > > + result->tx_fd = fd; > > + result->remote_addr_size = 0; > > + result->remote_addr = NULL; > > + return result; > > + > > +fd_cleanup: > > + if (fd >= 0) > > + os_close_file(fd); > > + if (result != NULL) > > + kfree(result); > > + return NULL; > > +} > > + > > static struct vector_fds *user_init_raw_fds(struct arglist *ifspec) > > { > > int rxfd = -1, txfd = -1; > > @@ -578,6 +635,8 @@ struct vector_fds *uml_vector_user_open( > > return user_init_socket_fds(parsed, ID_L2TPV3); > > if (strncmp(transport, TRANS_BESS, TRANS_BESS_LEN) == 0) > > return user_init_unix_fds(parsed, ID_BESS); > > + if (strncmp(transport, TRANS_FD, TRANS_FD_LEN) == 0) > > + return user_init_fd_fds(parsed); > > return NULL; > > } > > > > > > We should also control enable/disable of recv/sendmmsg as an option here. > > It can be made generic and be fed into get_transport_options() in > vector_kern.c as an override.
So actually, there seems to be a way to do that already:
vec0:transport=fd,fd=N,vec=0
> > -- > Anton R. Ivanov > Cambridgegreys Limited. Registered in England. Company Number 10273661 > https://www.cambridgegreys.com/ >
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