can_send(9)

💅 can_send(9) — the Kernel API Manual page you've been waiting for 🎀

okay bestie, welcome to the Kernel API Manual section 9, where we talk about can_send — the little function that yeets a CAN frame out into the world (and, if you want, loops it back so your local besties can hear it too). ✨

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✨ NAME ✨

can_send — transmit a CAN frame (optional with local loopback) 🦋

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🌸 SYNOPSIS 🌸

int can_send (struct sk_buff *skb , int loop );

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🎀 ARGUMENTS 🎀

• skb — pointer to a socket buffer that's holding your CAN frame down in its data section. that's the cargo, bestie 📦
• loop — the loopback for listeners on local CAN sockets. and like… it's the recommended default! (yes, with the exclamation point, the manpage is that serious about it 💅)

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💖 DESCRIPTION 💖

so here's the tea ☕ — because of the loopback, this routine must not be called from hardirq context. like, don't do it. not the vibe. 🙈

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🔥 RETURN 🔥

the receipts, in order:

• 0 on success — slay, it worked 👑
• -ENETDOWN when the selected interface is down 😭
• -ENOBUFS on a full driver queue (check net_xmit_errno, iykyk)
• -ENOMEM when local loopback failed at calling skb_clone 💀
• -EPERM when you're trying to send on a non-CAN interface (wrong crowd, babe)
• -EMSGSIZE when the CAN frame size is bigger than the CAN interface MTU 🫠
• -EINVAL when skb->data does not contain a valid CAN frame — literally what are you even handing me

ngl, half of these are just the kernel gently telling you "no <3" — check your interface, your buffer, and your frame before you come for can_send.

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🌈 SEE ALSO 🌈

Kernel file ./net/can/af_can.c — plus the whole friend group: effhash(9), can_rcv_list_find(9), can_rx_register(9), can_rx_unregister(9), can_proto_register(9), can_proto_unregister(9). go say hi to all of them, they're iconic 🫶

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and that's the whole page, bestie 💜 — brought to you by ./net/can, dated October 2026. mwah, go transmit responsibly 🧚⭐