Embedded C Developer OpenSync/OpenWrt WiFi Router with Cellular Backup
hace 3 días
Englewood
Job Description JD: We're looking for an Embedded C Developer to work on next-generation residential gateway platforms that combine DOCSIS/fiber WAN connectivity with LTE/5G cellular backup. You'll be developing and maintaining firmware on OpenWrt-based hardware running the OpenSync framework, with direct impact on millions of deployed customer premises equipment (CPE). Responsibilities • Design, develop, and debug embedded C software for Linux-based residential gateway platforms (ARM/MIPS SoC), • Develop and maintain OpenSync managers — event-driven daemons that interact with OVSDB for cloud-managed configuration and state reporting, • Implement and optimize LTE/5G cellular failover and fallback logic including modem management, route arbitration, and WAN healthchecks, • Develop LED state machine logic to provide accurate device status indication across complex multi-WAN scenarios, • Interface with cellular modems via AT commands, QMI/MBIM, USB, and PCIe (MHI) protocols, • Work with WiFi drivers (Qualcomm/Broadcom/Atheros) for 2.4GHz, 5GHz, and 6GHz radio configuration, • Debug kernel-level issues including PCIe enumeration, USB device management, network driver crashes, and kernel panics, • Implement and maintain secure communication channels using TLS with mutual authentication and tunneling protocols, • Analyze and resolve field issues using device logs, crash dumps, and remote diagnostics, • Develop init scripts, UCI configuration handlers, and persistent storage management for OpenWrt, • Write unit tests and participate in code reviews via GitLab merge requests, • Collaborate with hardware teams, QA, cloud platform engineers, and service provider partners Required Skills • 5 years of embedded C development on Linux-based platforms, • Strong proficiency in C programming — pointers, memory management, IPC, event-driven architectures, • Experience with OpenWrt build system, package management, UCI configuration, and JFFS2/SquashFS overlay filesystems, • Familiarity with OpenSync or similar cloud-managed CPE frameworks (OVSDB, protobuf, MQTT telemetry), • Experience with cellular modem integration — AT commands, QMI, network interface management (rmnet/wwan), • Strong understanding of Linux networking — routing tables, metrics, netfilter, bridge interfaces, IPv4 and IPv6 dual-stack, neighbor discovery, DHCPv4/DHCPv6, SLAAC, and prefix delegation, • Understanding of TLS handshake with mutual authentication using X.509 certificates, certificate chain validation, and secure provisioning, • Knowledge of security and tunneling protocols — GRE tunneling, IPsec, VPN overlays, and secure encapsulation for cloud-managed traffic, • Experience with event loop frameworks (libev, libuv, or similar), • Proficiency with debugging tools — GDB, strace, tcpdump, kernel logs, serial console, • Familiarity with Git, GitLab CI/CD, cross-compilation toolchains, • Understanding of WiFi standards (802.11ax/be) and wireless driver configuration Preferred Skills • Experience with Qualcomm IPQ series SoCs (IPQ5018, IPQ9574) and NSS/PPE data path, • Experience with Broadcom BCM series chipsets (BCM4908, BCM6750, BCM63178) and Memory Direct Engine (MDE) / hardware acceleration, • Knowledge of Atheros/QCA/BCM wireless chipsets and CFG80211/mac80211 driver architecture, • Knowledge of DOCSIS cable modem interaction and WAN interface management, • Experience with PCIe and USB subsystems in embedded Linux (device enumeration, power management, error recovery), • Familiarity with eSIM/eUICC provisioning (LPA, GSMA SGP.22), • Experience with carrier aggregation, NR5G NSA/SA, and multi-band cellular configurations, • Understanding of TR-069/TR-369 (USP) device management protocols, • Basic understanding of TR-181 data model for CPE device management and service configuration, • Experience with Kconfig-based build configuration, • Knowledge of flash storage considerations — wear leveling, persistent partitions, factory reset flows, • Familiarity with thermal management and power management (battery-powered CPE) Tools & Technologies • Languages: C, Shell scripting (sh/bash), Python (test automation), • OS/Platform: OpenWrt (Linux 5.x/6.x kernel), ARM Cortex-A53/A73, • Frameworks: OpenSync, OVSDB, libev, protobuf-c, jansson (JSON), • Chipsets: Qualcomm IPQ, Broadcom BCM, Atheros/QCA, • Networking: iproute2, iptables/nftables, ovsdb-server, hostapd/wpa_supplicant, GRE, IPsec, • Security: OpenSSL/mbedTLS, X.509 certificates, mTLS, certificate management, • Cellular: Qualcomm QCM/SDX modems, MHI, qcserial, AT QENG/AT COPS, • Protocols: IPv4, IPv6, DHCPv4/v6, DNS, MQTT, GRE, TLS 1.2/1.3, • Build: Make, Kconfig, OpenWrt feeds, cross-compilation (musl/glibc), • Debug: GDB, valgrind, serial console, logpull analysis, • VCS/CI: Git, GitLab, merge request workflows Nice to Have • Experience working directly with ISP/MSO/OEM partners, • Exposure to hardware bring-up and board support package (BSP) development, • Experience with Agile/Scrum in a firmware development context, • Familiarity with SCTE/DOCSIS standards, • Understanding of TR-181 data model parameters for WAN management, WiFi configuration, and device monitoring, • Experience with GRE tunnel implementation for backhaul traffic in managed WiFi deployments What You'll Work On • Cellular failover/fallback state machines with sub-second transition handling, • LED indication logic for multi-WAN connectivity states, • Modem health monitoring and subsystem restart/recovery, • Internet reachability healthcheck frameworks, • Cloud-managed device configuration and telemetry reporting via MQTT, • Secure cloud connectivity using mTLS with X.509 certificate-based mutual authentication, • GRE tunnel management for cloud-redirected traffic, • Factory reset, firmware upgrade, and persistent storage management, • IPv4/IPv6 dual-stack network configuration, routing, and failover across DOCSIS and LTE interfaces, • WiFi radio configuration and performance optimization across Qualcomm / Broadcom platforms, • Kernel crash analysis and driver-level bug resolution Top Skills: 1. Embedded C Development on Linux/OpenWrt o C programming, Linux internals, debugging, IPC, event-driven design 1. OpenSync/OpenWrt Platform Development o OpenSync Managers, OVSDB, UCI, MQTT, OpenWrt build system 1. Linux Networking & LTE/5G Cellular Integration o Routing, IPv4/IPv6, failover, QMI/MBIM, modem management, GRE/IPsec Additional Details: Team size 8 Direct report - None Key Deliverables : Responsibilities • Design, develop, and debug embedded C software for Linux-based residential gateway platforms (ARM/MIPS SoC), • Develop and maintain OpenSync managers — event-driven daemons that interact with OVSDB for cloud-managed configuration and state reporting, • Implement and optimize LTE/5G cellular failover and fallback logic including modem management, route arbitration, and WAN healthchecks, • Develop LED state machine logic to provide accurate device status indication across complex multi-WAN scenarios, • Interface with cellular modems via AT commands, QMI/MBIM, USB, and PCIe (MHI) protocols, • Work with WiFi drivers (Qualcomm/Broadcom/Atheros) for 2.4GHz, 5GHz, and 6GHz radio configuration, • Debug kernel-level issues including PCIe enumeration, USB device management, network driver crashes, and kernel panics, • Implement and maintain secure communication channels using TLS with mutual authentication and tunneling protocols, • Analyze and resolve field issues using device logs, crash dumps, and remote diagnostics, • Develop init scripts, UCI configuration handlers, and persistent storage management for OpenWrt, • Write unit tests and participate in code reviews via GitLab merge requests, • Collaborate with hardware teams, QA, cloud platform engineers, and service provider partners unique selling points - Strong - Hands-on experience developing OpenSync-based OpenWrt gateway firmware with LTE/5G cellular failover, combining deep Embedded C expertise, Linux networking, and cloud-managed CPE platforms.